i68 
ZOOLOGY OF THE FAR EAST. 
in width. Most of the larger individuals carry numerous young attached to the 
ventral surface of the body. 
External Characters. The dorsal surface is quite rough all over, owing to the pre- 
sence of numerous well developed conical papillae. These are of various sizes and 
form a transverse row of 22-27 on every ring. There seems, however, to be no regu- 
larity as to their arrangement longitudinally, so that no well-defined longitudinal rows 
are formed, such as are characteristic of many species of Glossiphonia and Placohdella. 
Even the papillae lying about the median line do not form a regular row, some being 
placed a little to the right and some a little to the left. In each transverse row the 
papillae are arranged, as a rule, symmetrically, those of the same size occupying 
corresponding position on both sides of the median line. Posterior to the geni- 
tal orifices every third annulus has smaller and more numerous papillae than the 
intervening ones. This is most striking in a few somites in front of the posterior 
sucker, where the annuli bearing smaller papillae are less than half so broad as 
those preceding or succeeding them (pi. vii, fig. 7). The ventral surface is entirely 
smooth. 
The colour in alcohol is a uniform grey, with a faint brownish streak along the 
median line of the dorsal surface. On the ventral side it is much paler. Many of 
the specimens have the lateral margins dotted with brown. 
Somites I — III are uniannulate, IV and V are biannulate, each being divided into 
a larger anterior and a smaller posterior annulus (pi. vii, fig. 8). Nineteen somites, 
VI — XXIV, are triannulate. The three remaining somites, XXV — XXVII, are uni- 
annulate, and are much narrower transversely than the preceding ones (pi. vii, fig. 7). 
The total number of annuli is, accordingly, sixty-seven. As shown in the figure, the 
typical somite consists of three annuli of approximately equal size, the middle one 
of which bears markedly smaller papillae than the other two (pi. vii, fig. 6) . In somites 
XXIII and XXIV the second annulus is itself very small and carries only minute 
papillae. As there is no biannulate somite in the posterior region, the transition from 
the triannulate to uniannulate somite is rather abrupt, causing the last three rings 
to appear like the peduncle of the sucker. 
There is apparently a single pair of eyes placed close together in the anterior part 
of the third annulus. As they are rather large it is possible that each represents 
two eyes belonging to two consecutive rings fused together. 
The oral sucker has the usual shape and is rather large, measuring nearly 15 
mm. across. It occupies the ventral side of the annuli 1-5. The annuli 6 and 7 are 
fused on the ventral side and form the posterior boundary of the .sucker. The mouth 
opening is placed on the lower surface of the anterior lip a little distance from the 
margin. 
The male genital orifice hes between the annuli 25 and 26, i.e. between somites 
XI and XII. The female pore is situated between the annuH 27 and 28, i.e between 
the second and third ring of somite XII. 
I was unable to find a well defined clitellum in any of the specimens, nor could 
I detect the external openings of the nephridia. 
