480 



AETICULATA. 



[Chap. XIII. 



which are too hot and dry for them ; but amongst the 

 rank vegetation in the lower ranges of the hill country, 



may "be a H. Boscii, distinct 

 from the H. Ceylanica. That 

 which is found in Ceylon is round, 



EYES AND TEETH OF THE LAND 

 LEECH OP CEYLON. 



a little flattened on the inferior 

 surface, largest at the anal ex- 

 tremity, thence gradually tapering 

 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 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 in- 

 tervening. To Mr. Thwaites, Di- 

 rector of the Botanic Garden at 

 Peradenia, who at my request ex- 

 amined 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 cut- 

 ting instruments, is principally 

 muscular, the muscular body being 

 very clearly seen. The rounded 

 edge in which the teeth are set ap- 

 pears to be cartilaginous in struc- 

 ture ; the teeth are very numerous, 

 (fig. B) ; but some near the base 

 have a curious appendage, appa- 

 rently (I have not yet made this 

 out quite satisfactorily) 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 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 

 diners 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." 



