Sketches of the Natural History of Ceylon Part 92

[Footnote 2: _Ann. Nat. Hist_. April, 1852. Paper by Mr. EDGAR L.

LAYARD.]

_Painted Crabs_.--On the reef of rocks which lies to the south of the harbour at Colombo, the beautiful little painted crabs[1], distinguished by dark red markings on a yellow ground, may be seen all day long running nimbly in the spray, and ascending and descending in security the almost perpendicular sides of the rocks which are washed by the waves. _Paddling Crabs_[2], with the hind pair of legs terminated by flattened plates to a.s.sist them in swimming, are brought up in the fishermen's nets. _Hermit Crabs_ take possession of the deserted sh.e.l.ls of the univalves, and crawl in pursuit of garbage along the moist beach.

Prawns and shrimps furnish delicacies for the breakfast table; and the delicate little pea crab, _Pontonia inflata_[3], recalls its Mediterranean congener[4], which attracted the attention of Aristotle, from taking up its habitation in the sh.e.l.l of the living pinna.

[Footnote 1: _Grapsus strigosus_, Herbst.]

[Footnote 2: _Neptunus pelagicus_, Linn.; _N. sanguinolentus_, Herbst, &c. &c.]

[Footnote 3: MILNE EDW., _Hist. Nat. Crust_., vol. ii. p. 360.]

[Footnote 4: _Pinnotheres veterum_.]

ANNELIDae.--The marine _Annelides_ of the island have not as yet been investigated; a cursory glance, however, amongst the stones, on the beach at Trincomalie and in the pools that afford convenient basins for examining them, would lead to the belief that the marine species are not numerous; tubicole genera, as well as some nereids, are found, but there seems to be little diversity, though it is not impossible that a closer scrutiny might be repaid by the discovery of some interesting forms.

_Leeches_.--Of all the plagues which beset the traveller in the rising grounds of Ceylon, the most detested are the land leeches.[1] They are not frequent in the plains. which are too hot and dry for them; but amongst the rank vegetation in the lower ranges of the hill country, which is kept damp by frequent showers, they are found in tormenting profusion. They are terrestrial, never visiting ponds or streams. In size they are about an inch in length, and as fine as a common knitting needle; but they are capable of distension till they equal a quill in thickness, and attain a length of nearly two inches. Their structure is so flexible that they can insinuate themselves through the meshes of the finest stocking, not only seizing on the feet and ankles, but ascending to the back and throat and fastening on the tenderest parts of the body.

In order to exclude them, the coffee planters, who live amongst these pests, are obliged to envelope their legs in "leech gaiters" made of closely woven cloth. The natives smear their bodies with oil, tobacco ashes, or lemon juice[2]; the latter serving not only to stop the flow of blood, but to expedite the healing of the wounds. In moving, the land leeches have the power of planting one extremity on the earth and raising the other perpendicularly to watch for their victim. Such is their vigilance and instinct, that on the approach of a pa.s.ser-by to a spot which they infest, they may be seen amongst the gra.s.s and fallen leaves on the edge of a native path, poised erect, and preparing for their attack on man and horse. On descrying their prey they advance rapidly by semi-circular strides, fixing one end firmly and arching the other forwards, till by successive advances they can lay hold of the traveller's foot, when they disengage themselves from the ground and ascend his dress in search of an aperture to enter. In these encounters the individuals in the rear of a party of travellers in the jungle invariably fare worst, as the leeches, once warned of their approach, congregate with singular celerity. Their size is so insignificant, and the wound they make is so skilfully punctured, that both are generally imperceptible, and the first intimation of their onslaught is the trickling of the blood or a chill feeling of the leech when it begins to hang heavily on the skin from being distended by its repast. Horses are driven wild by them, and stamp the ground in fury to shake them from their fetlocks, to which they hang in b.l.o.o.d.y ta.s.sels. The bare legs of the palankin bearers and coolies are a favourite resort; and, as their hands are too much engaged to be spared to pull them off, the leeches hang like bunches of grapes round their ankles; and I have seen the blood literally flowing over the ledge of a European's shoe from their innumerable bites. In healthy const.i.tutions the wounds, if not irritated, generally heal, occasioning no other inconvenience than a slight inflammation and itching; but in those with a bad state of body, the punctures, if rubbed, are liable to degenerate into ulcers, which may lead to the loss of limb or even of life. Both Marshall and Davy mention, that during the march of troops in the mountains, when the Kandyans were in rebellion, in 1818, the soldiers, and especially the Madras sepoys, with the pioneers and coolies, suffered so severely from this cause that numbers perished.[3]

[Footnote 1: _Haemadipsa Ceylanica_. Bose. Blainv. These pests are not, however, confined to Ceylon, they infest the lower ranges of the Himalaya.--HOOKER, vol. i. p. 107; vol. ii. p. 54. THUNBERG, who records (_Travels_, vol. iv. p. 232) having seen them in Ceylon, likewise met with them in the forests and slopes of Batavia. MARSDEN (_Hist_. p. 311) complains of them dropping on travellers in Sumatra. KNORR found them at j.a.pan; and it is affirmed that they abound in islands farther to the eastward. M. GAY encountered them in Chili.--(MOQUIN-TANDON, _Hirudinees_, p. 211, 346). It is very doubtful, however, whether all these are to be referred to one species. M. DE BLAINVILLE, under _H.

Ceylanica_, in the _Dict. de Scien. Nat_. vol. xlvii. p. 271, quotes M.

Bosc as authority for the kind, which that naturalist describes being "rouges et tachetees;" which is scarcely applicable to the Singhalese species. It is more than probable therefore, considering the period at which M. BOSC wrote, that he obtained his information from travellers to the further east, and has connected with the habitat universally ascribed to them from old KNOX'S work (Part 1. chap. vi.) a meagre description, more properly belonging to the land leech of Batavia or j.a.pan. In all likelihood, therefore, there may be a _H. Boscii_, distinct from the _H. Ceylanica_. That which is found in Ceylon is round, a little flattened on the inferior surface, largest at the a.n.a.l extremity, thence gradually tapering forward, and with the a.n.a.l sucker composed of four rings, and wider in proportion than in other species.

[Ill.u.s.tration: EYES AND TEETH OF THE LAND LEECH OF CEYLON]

It is of a clear brown colour, with a yellow stripe the entire length of each side, and a greenish dorsal one. The body is formed of 100 rings; the eyes, of which there are five pairs, are placed in an arch on the dorsal surface; the first four pairs occupying contiguous rings (thus differing from the water-leeches, which have an unoccupied ring betwixt the third and fourth); the fifth pair are located on the seventh ring, two vacant rings intervening. To Mr. Thwaites, Director of the Botanic Garden at Peradenia, who at my request examined their structure minutely, I am indebted for the following most interesting particulars respecting them. "I have been giving a little time to the examination of the land leech. I find it to have five pairs of ocelli, the first four seated on corresponding segments, and the posterior pair on the seventh segment or ring, the fifth and sixth rings being eyeless (_fig_. A). The mouth is very retractile, and the aperture is shaped as in ordinary leeches. The serratures of the teeth, or rather the teeth themselves, are very beautiful. Each of the three 'teeth,' or cutting instruments, is princ.i.p.ally muscular, the muscular body being very clearly seen. The rounded edge in which the teeth are set appears to be cartilaginous in structure; the teeth are very numerous, (_fig_. B); but some near the base have a curious appendage, apparently (I have not yet made this out quite satisfactorily) set upon one side. I have not yet been able to detect the a.n.a.l or s.e.xual pores. The a.n.a.l sucker seems to be formed of four rings, and on each side above is a sort of crenated flesh-like appendage. The tint of the common species is yellowish-brown or snuff-coloured, streaked with black, with a yellow-greenish dorsal, and another lateral line along its whole length. There is a larger species to be found in this garden with a broad green dorsal fascia; but I have not been able to procure one although I have offered a small reward to any coolie who will bring me one." In a subsequent communication Mr.

Thwaites remarks "that the dorsal longitudinal fascia is of the same width as the lateral ones, and differs only in being perhaps slightly more green; the colour of the three fasciae varies from brownish-yellow to bright green." He likewise states "that the rings which compose the body are just 100, and the teeth 70 to 80 in each set, in a single row, except to one end, where they are in a double row."]

[Ill.u.s.tration: LAND LEECHES IN PURSUIT]

[Footnote 2: The Minorite friar, ODORIC of Portenau. writing in A.D.

1320, says that the gem-finders who sought the jewels around Adam's Peak, "take lemons which they peel, anointing themselves with the juice thereof, so that the leeches may not be able to hurt them."--HAKLUYT, _Voy._ vol. ii. p. 58.]

[Footnote 3: DAVY'S _Ceylon_, p. 104; MARSHALL'S _Ceylon_, p. 15.]

One circ.u.mstance regarding these land leeches is remarkable and unexplained; they are helpless without moisture, and in the hills where they abound at all other times, they entirely disappear during long droughts;--yet re-appear instantaneously on the very first fall of rain; and in spots previously parched, where not one was visible an hour before, a single shower is sufficient to reproduce them in thousands, lurking beneath the decaying leaves, or striding with rapid movements across the gravel. Whence do they re-appear? Do they, too, take a "summer sleep," like the reptiles, molluscs, and tank fishes? or may they, like the _Rotifera_, be dried up and preserved for an indefinite period, resuming their vital activity on the mere recurrence of moisture?[1]

[Footnote 1: See an account of the _Rotifera_ and their faculty of repeated vivifaction, in the note appended to this chapter.]

Besides a species of the medicinal leech, which[1] is found in Ceylon, nearly double the size of the European one, and with a prodigious faculty of engorging blood, there is another pest in the low country, which is a source of considerable annoyance, and often of loss, to the husbandman. This is the cattle leech[2], which infests the stagnant pools, chiefly in the alluvial lands around the base of the mountain zone, whither the cattle resort by day, and the wild animals by night, to quench their thirst and to bathe. Lurking amongst the rank vegetation that fringes these deep pools, and hid by the broad leaves, or concealed among the stems and roots covered by the water, there are quant.i.ties of these pests in wait to attack the animals on their approach to drink.

Their natural food consists of the juices of lumbrici and other invertebrata; but they generally avail themselves of the opportunity afforded by the dipping of the muzzles of the animals in the water to fasten on their nostrils, and by degrees to make their way to the deeper recesses of the nasal pa.s.sages, and the mucous membranes of the throat and gullet. As many as a dozen have been found attached to the epiglottis and pharynx of a bullock, producing such irritation and submucous effusion that death has eventually ensued; and so tenacious are the leeches that even after death they retain their hold for some hours.[3]

[Footnote 1: _Hirudo sanguisorba_. The paddi-field leech of Ceylon, used for surgical purposes, has the dorsal surface of blackish olive, with several longitudinal striae, more or less defined; the crenated margin yellow. The ventral surface is fulvous, bordered laterally with olive; the extreme margin yellow. The eyes are ranged as in the common medicinal leech of Europe; the four anterior ones rather larger than the others. The teeth are 140 in each series, appearing as a single row; in size diminishing gradually from one end, very close set, and about half the width of a tooth apart. When full grown, these leeches are about two inches long, but reaching to six inches when extended. Mr. Thwaites, to whom I am indebted for these particulars, adds that he saw in a tank at Kolona Korle leeches which appeared to him flatter and of a darker colour than those described above, but that he had not an opportunity of examining them particularly.

[Ill.u.s.tration: DORSAL.]

[Ill.u.s.tration: VENTRAL.]

Mr. Thwaites states that there is a smaller tank leech of an olive-green colour, with some indistinct longitudinal striae on the upper surface; the crenated margin of a pale yellowish-green; ocelli as in the paddi-field leech; length, one inch at rest, three inches when extended.

Mr. E.L. LAYARD informs us, _Mag. Nat. Hist_. p. 225, 1853, that a bubbling spring at the village of Tonniotoo, three miles S.W. of Moeletivoe, supplies most of the leeches used in the island. Those in use at Colombo are obtained in the immediate vicinity.]

[Footnote 2: _Haemopsis paludum_. In size the cattle leech of Ceylon is somewhat larger than the medicinal leech of Europe: in colour it is of a uniform brown without bands, unless a rufous margin may be so considered. It has dark striae. The body is somewhat rounded, flat when swimming, and composed of rather more than ninety rings. The greatest dimension is a little in advance of the a.n.a.l sucker; the body thence tapers to the other extremity, which ends in an upper lip projecting considerably beyond the mouth. The eyes, ten in number, are disposed as in the common leech. The mouth is oval, the biting apparatus with difficulty seen, and the teeth not very numerous. The bite is so little acute that the moment of attachment, and the incision of the membrane is scarcely perceived by the sufferer from its attack.]

[Footnote 3: Even men, when stooping to drink at a pool, are not safe from the a.s.sault of the cattle leeches. They cannot penetrate the human skin, but the delicate membrane of the mucous pa.s.sages is easily ruptured by their serrated jaws. Instances have come to my knowledge of Europeans into whose nostrils they had gained admission and caused serious disturbance.]

ARTICULATA.

_APTERA_.

THYSANURA.

Podura _albicollis_.

_atricollis_.

_viduata_.

_pilosa_.

Arch.o.r.eutes _coccinea_.

Lepisma nigrofasciara, _Temp_.

_nigra._

ARACHNIDA.

Buthus afer. _Linn_.

Ceylonicus, _Koch_.

Scorpio _linearis_.

Chelifer librorum.

_oblongus_.

Obisium _cra.s.sifemur_.

Phrynus lunatus, _Pall_.

Thelyphonus caudatus, _Linn._

Phalangium _bisignatum_.

Mygale fasciata, _Walck_.

Olios taprobanius, _Walck_.