Hirudinea. 
169 
The posterior sucker is cup-shaped as usual, and measures about 2 5 mm. in dia- 
meter. It is attached to the ventral side of the last three rings. The anus is placed 
on the dorsal surface of the hinder sucker inunediately behind the last annulus. 
Internal Anatomy. The mouth leads into the usual pharyngeal sac which extends 
backwards into about somite IX. In it lies the tubular proboscis, into the posterior 
end of which opens on each side a bundle of unicellular salivary glands. Then follows 
the stomach produced laterally into seven pairs of coeca, the last of which passes 
backwards through about fourth somite and ends in somite XXIV. The shape of the 
coeca is like those of Hemiclepsis marginata , but in quite small specimens the first six 
are simple, only the last showing ramifications corresponding to the somites. The 
intestine is produced as usual into four pairs of simple pouches, all enveloped in a 
sac-like dilatation of the dorsal blood vessel. 
The nephridia were not traced out fully, nor was the total number counted; the 
ciliated funnels were found to possess a form characteristic of the family. 
As to the generative organs I have nothing particular to mention. Both the 
male and female apparatus show, so far as I could make out, the same structure as 
those of H. marginata. 
Locality. Lampam, Patalung, Siam. Jan. 15, 1916. Numerous specimens* 
" Parasitic on the tortoise Bellia crassicollis." 
Systematic Position. I place this species in the genus Hemiclepsis on account of 
its great resemblance in structure to H. marginata, the type of the genus. It is also 
closely allied to the genus Placohdella, with which it agrees in almost all of the diag- 
nostic characters. In fact, the number of eyes and the position of the mouth-open- 
ing point rather toward a closer affinity with the latter, but the general shape of the 
body and especially that of the comparatively large oral sucker speak in favour of its 
inclusion in the former. The difference in the number of eyes can not be looked upon 
as very important, as in the genus Placohdella the eyes are compound, as the}^ prob- 
ably are in the present species. The presence of numerous papillae, the position of 
the genital orifices separated by two annuli, the number and form of the gastric coeca, 
even the parasitic mode of life with the tortoise as host are the same in both genera. 
If we except, therefore, the number of eyes, the only distinctive characters would be 
the position of mouth for Placohdella and the shape of the head for Hemiclepsis. Now, 
the present species combines both these characters, though not very distinctly: the 
mouth opening is not at the margin of the anterior lip , but a short distance behind 
it, nor is the head region so markedly widened as in Hemiclepsis marginata, but only 
very slightly. vSuch being the case, I have thought best to regard it as a member of 
the genus Hemiclepsis occupying a position on the border between this genus and 
Placohdella. 
13. Ancyrobdella' biwae, n.g., n.sp. 
Plate VII, figs. 9—12. 
This is no doubt the most remarkable leech contained in the collection. It is 
interesting not only on account of its extraordinary characters, but also because it is 
i avxu'^a anchor, fiSeAAu leech. 
