522 Mr. C. R. Narayana Rao on the Anatomy of 



throughout the wall are oval cells, which form a definite 

 layer on the outer surface ; each cell coutaiua a deeply 

 staining protoplasmic mass and a central nucleus. Such 

 cells occur over the entire intestinal wall behind the 

 gizzards. The cavity of the intestine is lined by a double 

 layer of chloragogen and columnar cells. The latter are 

 irregular in outline, producing a jagged appearance on the 

 inner surface. Judged from the nature of the occurrence 

 and distribution of the oval cells, a great many of them are 

 found in the muscles of the body-wall, it is possible to infer 

 that they are associated with the absorption and trans- 

 mission of food. 



Alimentary appendages are present ; those on the softer 

 gizzards are extremely vascular. The vessels of these 

 appendages are derived either from the dorsal vessel or from 

 the supraintestinal trunk. 



The last heart is in somite 10. The dorsal vessel over the 

 gizzards and anteriorly is considerably stout, and follows a 

 more or less zigzag course. The most anterior heart is in 

 segment 6. In the majority of forms in my collection there 

 is a supra-intestinal vessel. The phenomenon of opacity is 

 common to the dorsal vessel and the last hearts. Secondary 

 commissures are only rarely present, as the occurrence of the 

 lateral longitudinal vessels is arbitrary. A supra- and an 

 infraneural vessel is present, the latter together with the 

 iierve-cord is visible through the transparent skin. The 

 distribution of the vessels is similar to the plan described 

 in D. somavarpatana. 



The testis-sacs depend from the remains of septum 9/10, 

 and occupy segments 10 and 11, Each sac is an irregular 

 oval body, more or less attached to the dorsal vessel and the 

 hearts by the mesenterial wall. Its histological structure 

 and arrangement of testis-cells and funnel are identical with 

 those of the anterior pair of vesicles described in D. soma- 

 varpatana. In the testis-sac the position of the funnel 

 is easily made out from the area of iridescent shimmer on 

 its wall. 



The sperm-duct leads off from the posterior ventral 

 margin of the sac, and forms a dense matted structure 

 adhering to the wall of the vesicle, which it partly covers. 

 The duct, which when in the matted condition occupies 

 nearly three somites, is fairly thick, due to the large 

 development of the circular muscles around the internal 

 ciliated epithelium, and when uncoiled is over 65 to 70 mm. 

 long. The duct enters the prostate at its apex, which is 

 slightly indented. 



