Zoological Illustrations Volume Iii Part 19

GENERIC CHARACTER.--See Pl. 170.

SPECIFIC CHARACTER.

_M. supra rufescens, strigis nigris varius; genis mentoque albentibus, striga nigra intermedia; rectricibus attenuatis, nigris, rufo marginatis._

Above rufous brown with black stripes; sides of the head and chin whitish, divided by a black stripe; tail feathers attenuated, black, the margins rufous.

Motacilla Africana. _Gmelin_, 1. _p._ 958.

Sylvia Africana. _Lath. Ind. Orn._ 2. _p._ 518. _Gen. Zool._ 10. 2.

_p._ 615.

African Warbler. _Lath. Syn._ 4. _p._ 436.

Curruca naevia. _C. B. Spei. Brisson. Ois._ 3. _p._ 390. _tab._ 22. _f._ 2. _Orn._ 1. _p._ 419.

Le Fluteur. _Vaill. Ois. d'Afrique._

_Le Vaill. Ois. d'Af._ 3. _pl._ 112. _f._ 2.

The characters of _Malurus_, together with a few observations on the birds composing it, I have already given at plate 170 of this work. Yet as the species are scattered in several distinct genera of the Linnaean school, I have here represented that which may be termed the type of the genus, as inst.i.tuted by Professor Temminck, and as modified by myself. On comparing the characters of _Timalia_ (a new genus of Dr. Horsfield's) with those of _Malurus_, they will be found to designate one and the same group of birds.

Indeed, the minute and interesting details, which Dr. Horsfield has given, put the question almost beyond doubt, and lead me to conclude, that the Doctor was not aware, at the time, that his genus was already recorded.

This bird is not uncommon at the Cape of Good Hope. The notes of the male (according to M. Le Vaillant) are soft and agreeable, much resembling those of a flute; the shortness of the wings renders its flight very low. The figure is of the natural size; and the bird has been so well described by Brisson and Latham, that it is needless to repeat what they have said; the figures both of Le Vaillant and Brisson are by no means accurate. The tail feathers are delicate and transparent; and those of the whole body very soft, with detached webs or _radii_, similar to Dr. Horsfield's _Timalia pileata_, and _gularis_.

Pl. 171

[Ill.u.s.tration]

UNIO fragilis.

_Fragile River Mussel._

GENERIC CHARACTER.--See Pl. 58.

SPECIFIC CHARACTER.

_U. testa transversim ovata, tenui, intus purpurascente; dentibus cardinalibus tuberculatis, sub-obsoletis._

Sh.e.l.l transversely oval, thin, within purple; cardinal teeth tuberculated, nearly obsolete.

Most fresh water bivalves are remarkably dest.i.tute of that variety of colouring, which diversifies the exterior of marine sh.e.l.ls, and renders their distinction comparatively easy. A uniform olive green, or brown tint, pervades all the fluviatile genera; their specific distinctions rest on characters which frequently require long and perplexing descriptions, but which can be explained by the artist with ease and precision. It follows, therefore, that accurate figures of these sh.e.l.ls are more particularly wanted; for, although Lamarck has described so many, the short descriptions which he has given, and the want of figures to elucidate them, render it impossible to determine accurately one half of the species which he has enumerated.

_Unio fragilis_ is princ.i.p.ally distinguished by the cardinal teeth: those in the right valves are 2; short, obtuse, and nearly obsolete, more resembling tubercles, than the crenated or striated teeth of this genus.

The left valve has one tooth rather sharper. In young sh.e.l.ls the ligamental margin is nearly straight, and its extremity somewhat angulated; but old sh.e.l.ls lose these appearances, and become perfectly oval. In both stages of growth the sh.e.l.l is very thin, convex, and the inside (near the umbones) purple. The slight development of the cardinal teeth brings this sh.e.l.l nearer to the genus _Anodon_, than any other _Unio_ which I have seen.

It inhabits the rivers of North America, and was sent to me by Professor Rafinesque.

Pl. 172

[Ill.u.s.tration]

AMPULLARIA reflexa,

_Purple Apple Snail._

GENERIC CHARACTER.--See Pl. 103.

SPECIFIC CHARACTER.

_A. testa ovato-globosa, laevi; spira ventricosa, obtusa, sub epidermide purpurea; apertura nigro-purpurascente; labio exteriore tenui, margine reflexo._

Sh.e.l.l ovate-globose, smooth; spire ventricose, obtuse; beneath the epidermis, purple; aperture blackish purple; outer lip thin, the margin reflected.

_Knorr_, _vol._ 5. _pl._ 5. _f._ 2. (uncoated.)

Ampullaria reflexa. _Swainson, in Tilloch's Ph. Mag._ _vol._ 61. _p._ 377.

The only record that I can find (in the works of the old writers) for this Ampullaria, is the figure by Knorr above quoted; it is obviously drawn from an uncoated specimen, although I have seen instances, where the blackish purple on the spire was so intense, as to obscure the thin epidermis which covered it. The peculiar character of the species, and in which it differs from all others, is in the outer margin of the lip; which is thin, rather spread out, and slightly reflected; the form of the sh.e.l.l resembles _A.

fasciata_, but the spire, instead of being pointed, is obtuse; the umbilicus, likewise, is smaller and more concealed. From the absence of a groove round the aperture, I conclude the operculum is h.o.r.n.y.

The size varies; perfect sh.e.l.ls are in my possession much smaller than the figure, and I have seen others much larger, and with the aperture more chesnut than purple.

I am not acquainted with its locality.