674 Memoirs of the Indian Museum. [Vol. V 



examples measuring about 160 mm. in length in front of the posterior sucker and 

 20 mm. in breadth at the middle of the body. 



The anterior sucker presents a cup-shaped deepening on the ventral side of the 

 head and is very rough, due to the presence of numerous minute papillae. The 

 upper lip is divided on its inferior surface into two lobes by a longitudinal groove, 

 at the base of which are found three small jaws arranged in the usual manner. The 

 jaw is provided with numerous papillae and armed with a single row of numerous 

 minute teeth. 



The posterior sucker is of a circular shape, not wider than the greatest breadth 

 of the body and also marked with some seven rows of transversely arranged papil- 

 lae. 



The rings are very conspicuous, on the dorsal side counting 102 in front of the 

 posterior sucker, of which rings 6 and 7 are fused ventrally to form the posterior 

 boundary of the anterior sucker. The same is true of rings 8 and 9. The last ring is 

 pierced by the anus, thus showing signs of subdivision. 



According to Oka's procedure 1 in determining the boundaries of somites, all 

 the rings are grouped, as is usual, into twenty- seven somites, of which somites I, 

 II, III and XXVII are uniannulate; somites IV, V, and XXVI biannulate; somites 

 VI, VII and XXV triannulate ; somites VIII and XXIV quadriannulate ; the fifteen 

 somites IX-XXIII are complete, consisting of five rings. 



There are five pairs of eyes, lying, as in all species of Hirudo, respectively in 

 rings 2, 3, 4, 6 and 9. 



The segmental papillae are arranged, as has been stated' by Blanchard, in eight 

 dorsal and six ventral rows. 



The male genital aperture is situated between rings 31 and 32, that is between 

 the fourth and fifth rings of somite XI. The female aperture is five rings behind 

 the male, that is between the fourth and fifth rings of somite XII. 



The nephridial pores in some specimens could be somewhat easily demonstrated 

 from the exterior. There are in all seventeen pairs, the pore lying in the furrow 

 separating the second and third rings of somites VIII-XXIV. 



The clitellum embraces the four somites X-XIII. 



This species, as has been described by Blanchard (loc. cit., 1897b) in detail, 

 exhibits great variation in colour and markings, so that their differences are purely 

 individual, and not such as to authorise even the distinction of "varieties." In the 

 majority of cases the ground colour of the dorsal surface in spirit is a brownish olive 

 with a slight touch of bluish grey. There are seven longitudinal rows of black 

 patches, one median and three lateral on each side. The median stripe is sometimes 

 of a dark brown colour and is in some cases continuous, the side of the median stripe 

 extending almost throughout the whole length of the body. On each is seen a row 

 of patches which mark in most instances the first and last rings of each complete 



1 Oka, A., 1917. Hirudinea. Zoological Result of a Tour in the Far East. Mem. Asiat. Soc. 

 Bengal, Vol. VI. 



