302 



ZOOLOGY. 



[Part IT. 



ill the rising grounds of Ceylon, tlie most detested are 

 the land leeches.^ They are not frequent in the plains, 



^ Hc^madipsa Ceylanica, Boso. 

 Blainv. These pests are not, how- 

 ever, confined to Ceylon ; they infest 

 the lower ranges of the Himalaya. 

 — HooKEE, vol. i. p. 107 ; vol. ii. 

 p. 54. Thtjnbekg, 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 di-opping on tra- 

 vellers in Sumatra. Iinoer found 

 them at Japan ; and it is affirmed 

 that they abound in islands fai-ther 

 to the eastward. M. Gay encoim- 

 tered them in Chili. — Moquin- 

 Tandon, Hirudinees, p. 211, 34i3.) It 

 is very doubtfid, however, whether 

 all these are to be referred to one 

 species. M. de Blalnville, nnder 

 //. Ceylanica, in the Did. de Seien. 

 Nat. vol. xlvii. p. 271, qiiotes M. Bosc 

 as authority for the kind which that 

 natiu'alist describes being " rouges et 

 tachetees ; " which is scarcely ap- 

 plicable 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 i. 

 chap, vi.) a meagi-e description, more 

 properly belonging to the land leech 

 of Batavia or Japan. In all like- 

 lihood, therefore, there may be a 

 H. Boscii, distinct from the H. Cey- 



lanica. That wliich is found in Cey- 

 lon is round, a little flattened on the 

 inferior surface, largest at the anal 

 extremity, thence gradually taper- 



ing forward, and with the anal sucker 

 composed of four rings, and wider in 

 proportion than in other species. 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 siu*- 

 face ; the first four pairs occupying 

 contiguous rings (thus differing from 

 the water-leeches, which have an un- 

 occupied ring betwixt the third and 

 fourth); the fifth pair are located on 

 the seventh ring, two vacant rings in- 

 tervening. To l)r. Thwaites, Director 

 of the Botanic Garden at Peradenia, 

 who at my request examined their 

 structure minutely, I am indebted for 

 the following most interesting particu- 

 lars 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 

 ruigs being eyeless {Jiy. A). The 

 mouth is veiy retractile, and the 

 apertiu-e 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 instnmients, is 

 principally muscidar, the muscidar 

 body being very clearly seen. The 

 rounded edge in which the teeth are 

 set appears to be cartilaginous in 

 structure ; the teeth are very nume- 

 rous, {fiy. B) ; but some near the base 

 have a curious appendage, apparently 

 (I have not yet made this out quite sa- 

 tisfactorily) set upon one side. I have 

 not yet been able to detect the anal 

 or sexual pores. The anal 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 yellow- 

 ish-brown or snuff-coloured, streaked 

 with black, with a yellow-greenish 

 dorsal, and another lateral line along 



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