in specimens two oi" threo nim. long, their function soGms 

 lost, though they persist as small masses of cells in the 

 adult. 



Sense-Organ of the Genital Papilla. - Ono of the pairs 

 of nerves of the anterior ganglion has been described as 

 going to the kidneys and genital papillae. Situated just 

 at the junction of the ectodermal genital duct, with the 

 sexual organ there is an organ v/hich by its structure 

 seems to be for special sensation. The nerve to it (figs. 

 65,. 64) after a very short course is distributed to senso- 

 ry cells which lie adjacent to the epithelial lining of 

 the genital duct. The sensory cells are long spindle- 

 shaped, and send their peripheral ends to terminate among 

 the epithelial cells lining the genital duct. Their cen- 

 tral ends I have not traced into the nerve, but it seems 

 justifiable to suppose that this is their connection. What 

 the function of this organ is I cannot state. V-Tiile the 

 figures apparently show it somo distance from the exterioi;. 

 it should be remembered that in "Ship-worms" 30 cm. long, 

 the sexual duct is less than a half mm. long, and that the 



