Discoveries in Australia Volume I Part 42

Cristiceps axillaris. RICHARDSON.

CH. SPEC. C. pinnis intaminatis; macula argentata post os maxillare, altera in summa gena pone oculum et tertia majori in axilla pectorali; linea laterali argenteo-punctata.

RADII. B.6; D. 3 : --28 : 7; A. 2 : 25; C. 11; P. 11; V.1 : 2.

FISHES. PLATE 1. Figures 1, 2, 3.

This singularly delicate and clear-looking fish has, after long immersion in spirits, a pale flesh colour, with transparent and spotless fins. A bright silvery streak descends from the angle of the preorbitar to the corner of the mouth, where it dilates a little. A speck of the same colour exists within the upper limb of the preoperculum, and immediately behind the pectoral fin there is a large oblong one. The little tubes forming the lateral line are also silvery. It is with much doubt that I name this species as distinct from the C. australis of the Histoire des Poissons, but there some points in M. Valenciennes' description of that fish which I cannot reconcile with the specimen now under consideration.

And first, with respect to scales, M. Valenciennes states that he could detect none in australis, but in axillaris there are minute round scales, lying rather wide of each other, each having central umbo and lines radiating from it to the circ.u.mference. These scales are not easily seen while the skin continues moist, but become apparent as it dries, and are most numerous towards the tail. The head of axillaris is scaleless, and a row of pores runs along the lower jaw, up the preoperculum, and along the temporal groove. The eye is also encircled by similar pores. The muscular fibres shine through the delicate skin as in australis, and the teeth on the jaws and vomer appear to be similar. On comparing the specimen of axillaris with the figure of australis in the Histoire des Poissons, the second dorsal does not appear undulated as in the latter, but the spinous rays increase gradually in height from the first, and the anterior dorsal is proportionally higher; the distance also between the ventrals and a.n.u.s is considerably less in proportion to the length of the head, which is contained four times and a half in the total length of the fish, while the height of the body is contained five times. The proportions of australis are stated differently. Length of specimen, 3.42 inches.

HABITAT. King George's Sound (Benj. Bynoe, Esquire Surgeon of the Beagle).

Since the above notice was drawn up I have examined a cristiceps upwards of six inches long, which was sent from Botany Bay by Sir Everard Home to the College of Surgeons. This does not clear up the doubt respecting the ident.i.ty of australis and cristiceps. It has completely lost its colours, and shows neither the greenish bands of australis, nor the silvery marks of axillaris, it has, however, the form of the fins of the latter, with the number of rays exactly as in australis, a s.p.a.ce between the ventrals and a.n.u.s equal to the length of the head, scales on the body, as in axillaris, and similar pores on the head. Better materials are required to enable us to decide whether axillaris be a nominal species or not.

Scorpaena stokesii. RICHARDSON.

RADII. D. 12 : 9; A. 3 : 5; C. 13 6/6; P. 17; V. 1 : 5.

FISHES. PLATE 2. Figures 6, 7, 8, and 9, natural size.

The Scorpaenae have so strong a generic resemblance among themselves that it is difficult to detect the distinctive characters of the species, especially as the colours of the recent fish speedily fade when macerated in spirits, or when the mucous integument decays or is injured. We have received but a single example of the subject of this article, which is named in honour of the able commander of the Beagle.

The species bears a near resemblance to the Scorpaena militaris, but differs from it in having no spinous point terminating the intra orbitar ridges, and in the distribution of the scales on the cheek and gill cover. The spinous points on the head approach very near to those of bufo and porcus. The inferior preorbitar tooth is acutely spinous, and points directly downwards; the two anterior ones are inconspicuous, and not very acute, and the smaller upper posterior one observed in most Scorpaenae is obsolete, or, at least, completely hidden by the integuments. The nasal spines are, as usual, small, simple, and acute. The three supra orbitar teeth are smaller than in militaris, and the middle one reclines so as to be concealed by the integument instead of standing boldly up. The two low ridges between the orbits do not end in spinous points. The lateral ridges continued from the orbits over the supra scapulars, and the temporal ridges which are parallel to them, but run farther back, contain each four teeth. The infra-orbitar ridge is slightly uneven anteriorly, and two reclining teeth may be made out at its posterior end. The preoperculum is curved in the segment of a circle, and has a short spine, with a smaller one on its base, opposite to the abutment of the infra-orbitar ridge. Beneath this spine there are four angular points on the edge of the bone. The opercular spines are as usual two in number, being the tips of two low even divergent ridges, with a curved notch in the edges of the bone between them. The coracoid bone is notched above the pectoral fin, the notch being terminated below by a spine, and above by an acute corner. There are no scales between the cranial ridges on the top of the head, nor in the concave inter-orbital s.p.a.ce. A single row of five or six scales traverses the cheek below the infra-orbitar ridge. The temples before the upper limb of the preoperculum are densely scaly, as is also the gill flap above the upper opercular ridge. The acute membranous lobe which fills the notch between the two opercular spines is likewise scaly, and there are a few scales about the origin of the ridges, but the s.p.a.ce between the ridges, the sub-operculum, and the inter-operculum, are naked.

There is a short fringed superciliary cirrhus, and some slender filaments from other parts of the head, as shown in the figure, also lax skinny tips on the inferior points of the preorbitar and preoperculum, but the condition of the specimen does not admit of other cirrhi being properly made out if such actually existed. In the axilla of the pectoral there are four or five pale round spots. The figure, which is of the natural size, represents the markings which remain after long maceration in weak spirit. If there be a black mark in the first dorsal, as in the militaris, it is effaced in our specimen. Length, 2.4 inches.

HABITAT. The coasts of Australia.

Smaris porosus. RICHARDSON.

CH. SPEC. Smaris rostro porosissimo; fascia obscura e rostro per oculum recte ad caudam tracta; fascia altera in summo dorso.

RADII. B. 6; D. 10 : 9; A. 3 : 7; C. 15 5/5; V. 1 : 5.

FISHES. PLATE 3.

This Smaris has fewer dorsal rays than any species described in the Histoire des Poissons, and a shorter body than the Mediterranean vulgaris. Its shape is fusiform, the greatest height, which is at the ventrals, and which exceeds twice the thickness, being contained exactly four times in the total length, caudal included. The thickness at the gill cover is greater than that of the body, which lessens very gradually to the end of the tail. The snout is transversely obtuse, but is rather acute in profile. A cross section of the body at the ventrals is ovate, approaching to an oval, the obtuse end being upwards. In profile the curve of the belly is rather greater than that of the back, and the face slopes downwards to the mouth, nearly in a straight line.

The head forms rather less than a quarter of the whole length. The eye is large, and approaches near the profile without trenching on it. The mouth is scarcely cleft so far back as the nostrils. The intermaxillaries are moderately protractile, and curve a little downwards.

The teeth are disposed on the jaws in rather broad villiform bands, the individual teeth being setaceous and erect. They become a little taller nearer the outside, and the outer terminal cross row, composed of three on each side of the symphysis, may be termed small canines. On the lower jaw the villiform teeth in front are more uniformly small, and there is an acute row of subulate teeth, which are tallest in the middle of the limbs of the jaw, beyond which, towards the corners of the mouth, there is an even row of very small teeth. At the end of the jaw there is a small canine on each side exterior to all the others.

The fore edge of the preorbitar is slightly curved in form of the italic f, the lower corner curving forward abruptly, so as to produce a notch, which is filled up by the extremity of the retracted maxillary. The whole end of the snout, back to the eyes, including the disk of the preorbitar, is minutely porous, and a row of large pores borders the upper half of the orbit.

The jaws, the uneven lobate disk of the preoperculum and the branchiostegous membrane are naked, the rest of them being scaly. The scales of the cheek are disposed in six concentric curves, the same arrangement extending to the gill-cover, but less conspicuously. A small flat spinous point projects beyond the scales of the operculum, which has a very narrow membranous edging. The scales are ciliated. The caudal is slightly notched at the end, its basal half is scaly, as is also the base of the pectorals; the rest of the fins are scaleless. The dorsal is nearly even, its height being, however, rather greatest at the fourth or fifth spine. Its end is rounded.

A dark stripe, commencing at the top of the snout, runs through the eye straight to the tail, and a fainter one occupies the summit of the back to the end of the dorsal. The curve of the lateral line rises above the lower stripe anteriorly, but coincides with it beyond the posterior end of the dorsal. The rest of the fish is silvery, and the fins are not marked. These colours are described from a specimen preserved in spirits.

Length, 5 inches.

HABITAT. King George's Sound. (Bynoe).

Chelmon marginalis. RICHARDSON.

Chelmon marginalis, Richardson, Annals and Mag. of Nat. Hist. 10, page 28, September 1842.

RADII. D.9 : 31; A. 3-2l; C. 17 3/3; P. 16; V. 1 : 5.

FISHES. PLATE 4. Natural size.

This fish is described in the Annals of Natural History from a dried specimen brought from Port Essington by Mr. Gilbert. It has very much the form of Chelmon rostratus, but wants the eye-like spot on the dorsal.

Several examples in spirits were brought by the officers of the Beagle from the north-west coast of Australia, all of which show a broad band pa.s.sing between the dorsal and a.n.a.l fins, which was not visible in the dried specimen. This band is bounded anteriorly by one, and posteriorly by two whitish lines. In the Annals the a.n.a.l fin is described as being more angular than the dorsal, but in the specimens in spirits the reverse appears to be the case. This variation depends on the degree or expansion of the fins, and both may be much rounded by pulling the rays apart. The exact distribution of the bands may be clearly made out from the figure, which is very correct. The rays of the fins probably vary in number in different individuals, and our careful enumeration of those specimens kept in spirits, as recorded above, gives two or three soft rays more in the dorsal and a.n.a.l, than we were able to detect in the dried skin.

Length, 5 1/4 inches.

HABITAT. Northern and north-western coasts of Australia.

a.s.sICULUS.

CH. GEN. Corpus compressissimum, a.s.sulaeforme: caput cra.s.sius, minus altum, declive. Os parvum. Maxilla inferior porifera, ore clauso ascendens, hinc, ore hiante, ultra maxillam speriorem modice protractam extensa.

Preoperculum margine integro nec spinifero, disco arcto, inaequali, esquamoso, genam squamosam postice et infra cingens. Operculum tridentatum: Suboperculum crenatum; utrumque et interoperculum latiusculum squamis satis magnis tecta. Dentes villiformes, minuti c.u.m dente canino in media utroque latere maxillae inferioris et trans apicem utriusque maxillae dentibus quatuor (vel s.e.x) fortioribus, altioribus, in serie exteriori ordinatis. Dentes vomeris et palati acuti, stipati minuti. Dentes pharyngei, acerosi inequales, acuti.

Membrana branchialis radiis s.e.x sustentata, interoperculis liberis, acc.u.mbentibus tecta.

Squamae satis magnae, nitidae ciliatae. Linea lateralis antice abrupte ascendens, dein dorso parallela et approximata, postice diffracta infraque per mediam caudam cursum resumens.

Pinnae magnae esquamosae. Pinna dorsi anique radiis tribus, spinosis, ceteris articulatis. Pinnae ventrales sub pectorales offixae, propter tenuitatem ventris invicem approximatae.

The strong resemblance which the subject of this article bears to the Pseudochromis olivaceus of Dr. Ruppell (Neue Worlbethiere, page 8, taf.

2, figure 3) induced me at first sight to refer it to the same genus, but on examination I found that very material alterations would require to be made in the generic characters a.s.signed to Pseudochromis,* to enable them to apply to our fish.

(*Footnote. M. Swainson, considering this name as very objectionable, has proposed Labristoma instead. Both names are founded on the resemblance which the fish bears to another genus, in whole or in part, and the objection which has been made to the one is equally valid against the other.)

The above character has therefore been drawn up, and ichthyologists may consider a.s.siculus, either as a proper generic form, or as merely a subgenus or subdivision of Pseudochromis, with an extended character, according to their different views of arrangement. The last named genus, as described and restricted by Dr. Ruppell, from whom all our knowledge of it is derived, has the jaw teeth disposed in a single row, and the minute palatine teeth of a sphaeroidal form. The operculum has its angle prolonged, and is not toothed, nor is the suboperculum crenated; and a considerable number of the rays of the dorsal fin, succeeding to the three spinous ones, are simple but flexible, the posterior ones only being articulated and divided in the usual manner. Linnaeus has briefly characterized two fish (Labrus ferrugineus, Bl. Schn. page 251, and Labrus marginalis, Id. page 263) which most probably belong, either to Pseudochromis or a.s.siculus, and which are to be placed, M. Valenciennes thinks, near Malacanthus, among the Labridae. Now, this family, according to M. Aga.s.siz, is essentially cycloid in the structure of its scales, although there is a slight departure from the rigid characters of the order in the serrated preopercular of Crenilabrus, Ctenolabrus, and some others, and in the spine bearing operculum of Malacanthus. The latter genus is, moreover, described by M. Aga.s.siz as possessing scales with toothed edges, and rough to the touch when the finger is drawn forwards.

It has the simple intestinal ca.n.a.l without caeca, which is proper to the Labridae. The intestine of Pseudochromis is similarly formed, the stomach being continuous with the rest of the alimentary ca.n.a.l, and not distinguished by any cul de sac. Having but one specimen of a.s.siculus for examination, I have not been able to submit it to dissection to see whether the structure of its intestines be the same or not, but both it and Pseudochromis differ very widely from the labroid type in their scales, possessing the peculiar firm, shining, strongly ciliated structure, which we observe in Glyphisodon and its allies, and in the lateral line being interrupted in a precisely similar manner. Chromis and Plesiops have already been removed by M. Valenciennes from the Labridae to the Glyphisodontidae, and it is with them that we feel inclined to range a.s.siculus and Pseudochromis, notwithstanding the discrepancies in the form of the intestinal ca.n.a.l. We can, however, trace a gradation in the variation of form. The normal number of caeca in the Glyphysodontidae is three. In Chromis there are generally two small ones, while the Bolti of the Nile, or the Chromis niloticus of Cuvier, has no pyloric caec.u.m, but a large cul de sac to the stomach. Malacanthus is widely separated from the Glyphisodontidae by its continuous lateral line. Since these remarks were written I have seen Muller's paper, ent.i.tled, Beitrage zur Kentniss der naturlichen Familien der Fische, in which the Chromidae are indicated as a distinct family from the Glyphisodontidae, which latter he names Labroidei stenoidei; and Pseudochromis, it is stated, belongs to neither of these families, because it has twofold pharyngeals with a division between them. Dr. Muller promises a separate article on Pseudochromis, which I have not yet seen.

a.s.siculus punctatus.