Dendy. — On a Neiv Zealand Fresh-water Leech. 101 



to be slightly variable, owing probably to the irregularity of 

 the atmulation. In a young specimen no eyes were visible 

 at all. The form of the eye, when viewed from above, is 

 crescentic, and on each side the two eyes lie back to back, 

 with the concavities of the pigment-cups facing away from 

 one another, one looking forwards and the other backwards. 



The mouth is placed well in front of and above the middle 

 of the anterior sucker, only a short way behind the marginal 

 median notch. 



The anus lies dorsally a short way in front of the posterior 

 sucker ; it may be separated from the sucker by two annuli. 



The male genital opening lies in what w T e count as the 

 thirteenth annulus behind the anterior sucker, so that if we 

 assume that the anterior sucker is composed of eight annuli 

 the male aperture may be located in annulus 21. The 

 aperture itself has tumid lips, and the annulus in its neigh- 

 bourhood is much swollen. Probably this annulus is com- 

 posed of two fused together, between which the aperture 

 lies,* but we have thought it desirable not to attempt a theo- 

 retical analysis. Some three or four of the annuli behind and 

 in the neighbourhood of the male aperture may exhibit a 

 well-marked longitudinal wrinkling. 



The actual female aperture was unrecognisable in our 

 specimens, but sections show that it must lie close behind 

 the male aperture, apparently in the groove between the 

 21st and 22nd annuli. Nephridial apertures could not be 

 recognised externally, but longitudinal sections showed seven 

 pairs, lying on annuli 31, 33, 35, 37, 39, 41, 43. 



Some specimens carried a number of eggs attached to the 

 ventral surface of the body in the brood-chamber before 

 mentioned. These eggs are ovoid in shape, and about - 5 mm. 

 in longer diameter. 



Internal Anatomy. 



The general anatomy agrees very closely with that of other 

 species, as described, for example, by Oka in his " Beitrage zur 

 Anatomie der Clepsine."t 



Alimentary Canal. — The mouth appears as a narrow trans- 

 verse slit in the cup-like anterior sucker. It leads into a 

 narrow tubular buccal cavity, through which the long muscular 

 proboscis can be protruded. When the proboscis is retracted 

 the buccal cavity extends back to about the 11th annulus. 

 The proboscis, or pharynx, is long and cylindrical, and in 

 ai state of retraction extends from about the 11th to about 

 the 25th annulus, lying in the middle of the body. From the 

 posterior end of the pharynx the narrow oesophagus runs for- 



* Compare Clepsine plana, Whitman, loc. cit. 



t " Zeitschrift fur wissenschaftliche Zoologie," band 58, 1894. 



