1920.] 



Fauna of the Chilka Lake : Hirudinea. 



515 



imperforate interior cup having a finely rib- 

 bed surface somewhat resembling that of the. 

 tip of the human finger. 



Posterior sucker circular, centrally at- 

 tached, narrower than the greatest width of 

 the body, broader in proportion to the body- 

 width in immature than in adult examples. 

 Annuli 71, two being pre-ocular. The second 

 and third annuli may show some division at 

 their margins : the fifth is confluent with the 

 free ventral edge of the anterior sucker : 

 annuli 6 and 7 are separate above but some- 

 times so slightly divided as to appear as 

 one ring : annulus 6 disappears ventrally, 

 leaving the seventh (distinguished by papil- 

 lae) to form the first ventral annulus fol- 

 lowing the anterior sucker. 



Complete somite formed of three annuli. 

 Somites i, ii and iii uniannulate ; iv, xxv, 

 xxvi and xxvii biannulate. The twenty 

 somites v-xxiv are complete with three 1 rings. 



Eyes, one pair, closely approximated, 

 situated normally in the third annulus, but 

 sometimes between the third and second 

 rings. 



Reproductive Organs, Digestive Tract, 

 Nephridiopores . 



Male genital orifice situated between annuli 

 26 and 27, that is, between somites xi and 

 xii ; female genital orifice situated two rings 

 behind the male, between annuli 28 and 

 29, being the second and third rings of 

 somite xii. 



Epididymis large, long and thrown into 

 complex coils and loops, the last loop ex- 

 tending as far down as the xvth somite, 

 and returning upwards through two somites 

 before again turning down to join the vas 



XVIII 



Cr. 7 



Fig. 2.- 



Placobdella emydae, n. sp. Diagram showing 

 annulation, genital organs, digestive tract 

 and other internal and external features. 

 The testes are shown on one side only, and the nephridiopores on the other for the sake of clearness, and 

 other organs have been treated in the same manner and for the same reason. Somites numbered in 

 Roman, and rings in ordinary figures. 



frb. Proboscis, sal. g, Salivary glands. Cr. I and 7, First and seventh diverticula of Crop. St, Stomach, int. Intes tine. an. anus. gang, one of the 

 ventral ganglia. ». 1 and ». 14, Nephridiopores of the first and fourteenth pair. Ep, Epididymis.^ vd, vas deferens, r. land t. 6, Testes of the first 

 and sixth pairs, ov. ovary. 



