618 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



through the wall of the renal chamber, in the region of the ciliated fold, 

 which opens into the pericardium. The ureter of the kidney (Figure 

 3, tirt.) is a small duct of uniform diameter, which follows the right 

 contour of the stomach-intestine, and opens ventral to, and slightly at 

 the left of, the anus. 



6. The Heart and Blood Gland. 



The blood gland is an irregular compact mass of minute round cells 

 lying dorsal to the suctorial bulb and anterior to the nerve collar. The 

 enlarged middle portion of the oviduct is often partly imbedded in 

 this gland. 



The heart consists of an anterior ventricle and a posterior auricle, 

 the latter being partly divided. The pericardial cavity is nearly filled 



by the distended heart, the walls of 



par. tis. c'onl. 



Figure 7. Edge of the ventricle 

 of the heart showing the brandling 

 muscular cells, par.tis.c'ont., connec- 

 tive-tissue wall. Camera liicida, one 

 inch ocular and one-twelfth inch 

 oil-immersion objective. X 612. 



which (Figure 7) are composed of 

 connective-tissue cells and branch- 

 ing cells, which are interpreted as 

 the contractile tissue of the heart 

 because they are so similar to the 

 evidently contractile cells of the 

 foot. The blood passes to the va- 

 rious parts of the body through 

 irregular sinuses, there being no 

 clearly defined blood vessels ap- 

 parent in my preparations. The 

 fact that the cavities of the gills 

 open directly into the secondary 

 coelom is submitted as further evi- 

 dence that there are no well defined 

 blood vessels. 



7. Anatomi/ and Histology of the 

 Heproductive System. 



The general features of the re- 

 productive system are similar to 

 those of most Nudibranchs. An hermaphroditic gland surrounds most 

 of the liver, the two organs forming a conspicuous mass and nearly fill- 

 ing the posterior half of the secondary coelom. The hermaphroditic 

 gland is usually designated as the posterior genital mass (Figure 3, 

 gen. p.), the anterior genital mass (gen. a.) consisting of the albumen 

 gland and the nidamental gland, which are united into one general body, 

 and a prostate gland. The prostate gland lies posterior to the albumen 



