162 ICHTHYOMENIA POROSA. 



As indicated (Plate 5, fig. 6), a dorsal coeciim is hut slightly developed, and 

 the intestine from its junction with the jiharynx to the cloaca is of uniform size 

 and character, and is jiouched in regular and characteristic fashion. Its walls 

 are composed of high club-shaped cells in which the small nuclei are basally 

 situated while the remaining portions are filled with large droplets of some 

 secretion unaffected by haematoxylin. Immediately beneath the gonad the 

 cells are much reduced in size, and are possessed of little if any glandular activity 

 but bear a heavy coat of cilia. Near the anterior end of the coelomoducts the 

 digestive canal narrows abruptly (Plate 6, fig. 1) to form a small canal which 

 arising near the ventral side of the animal makes its way dorsally on the under 

 side of the pericardium (Plate 24, fig. 5) to open into the cloaca. The cells 

 composing it are essentially the same as those lining the intestine beneath the 

 gonad. 



The hermaphrodite gland extends forward as far as the posterior limits 

 of the pharynx or slightly beyond (Plate 24, fig. 4) and in a sexually mature 

 animal contains ripe sex products throughout its entire extent. These originate 

 in the usual fashion and are in no wise peculiar save that the fully developed 

 eggs are unusually large, measuring 0.176 mm. Clearly defined tubes lead from 

 the gonad into the pericardium, which in the specimen represented in Plate 6, 

 fig. 1, contains both ova and sperms. The an tero- ventral pericardial wall is 

 ciliated and elsewhere cilia appear to be present though the true condition of 

 affairs is masked by the abundance of precipitated secretion. 



From the posterior end of the pericardium the coelomoducts arise as rela- 

 tively narrow canals lined with almost cubical cells bearing a coat of cilia similar 

 to those of the pericardium. Coursing downward and forward they gradually 

 increase in size and the walls, retaining their ciliated coat, develop several folds 

 before they unite with the limbs of the huge gland a short distance behind their 

 anterior boundaries. At about one fourth of the distance from the pericardial 

 opening to its outlet into the shell gland each tube originates what probably 

 functions as a seminal vesicle (Plate 6, -fig. 1). In calibre and histological fea- 

 tures each is similar to the neighboring parent canal with the exception of the 

 distal extremity which forms an enlarged, almost globular dilation. From 

 beginning to end the vesicula seminales contain spermatozoa in most cases 

 attached by their heads to the epithelial lining. Distal to the openings 

 into the vesicles the coelomoducts contain small quantities of spermatozoa, 

 unattached. 



At the junction of the dorsal and ventral limbs of the coelomoduct on each 



