INVERTEBRATE ZOOLOGY. 87 



and location of each part, and tlie relations of parts to each other. In this, 

 reference may be made to the follovWng tabulated view of the systems. For 

 details, refer to the different text books. 



63. Anatomical Synopsis. 



[In this, the order is that of preparation : the numbers refer to the seg- 

 ments.] 



1. Alimentary Canal. 



Mouth. With prostomium. 



Pharynx. A large oval mass, attached by muscular fibres to the 

 body-wall. 



Oesophagus. A long, narrow tube, surrounded by the hearts 

 (5-13). and bearing the — 



Oesophageal, or caleiferous glands. These are three pairs of lat- 

 eral diverticula of the oesophagiis. containing calcareous 

 bodies (11-13). 



CroiJ (Ingluvies). An oval shaped dilatation of the posterior end 

 of the oesophagus. Its walls are comparatively thin (14-16). 



Gizzard, or stomach {Ventriculns). A round mass with thick, 

 muscular walls (17-18). 



Intestine. A large tube of equal caliber throughout, with thin 

 walls disposed laterally in folds. A portion of the dorsal 

 wall is invaginated, forming the Typhlosole. (see cross-section) 

 19— to end. 



Liver mass {chloragogne cells). A diffused mass of yellow-brown 

 pyriform c-ells, covering the intestine dorsally and giving it 

 its yellow color. (Seen in cross-section ; also by isolating the 

 cells by scraping the canal very gentl}', and mounting tem- 

 porarily. ) 



2. Reproductive System (Hei-maphroditic). 

 (a) Male. 



Vesicula Soitlaalis {spermatic vesicle). A large rectangular, yel- 

 low-white organ, lying beneath and at the sides of the ali- 

 mentary canal (about 10-11), varying in extent in different 

 stages of development. Divided across into two portions : 

 the anterior expanded laterally into two paired lobes, and the 

 posterior into one. These lobes increase in size posteriorly, 

 and when well developed are recurved ui^on the main portion. 



