194 HANDBOOK OF INVERTEBRATE ZOOLOGY. 



The branchial chamber is thus shown to open externally, 

 and its manner of development shows that it is entirely- 

 external to the body cavity, and is formed by an infolding 

 of the shell, and its transparent roof (k) will be found to 

 be continuous, at each edge, with the ordinary calcified 

 shell which covers the rest of the body. Notice that the 

 branchial chamber runs back onto the flancs for some dis- 

 tance beyond the most posterior gill, and that there is a 

 flat, muscular band along its edge. 



o. The space between the stomach in front and inter- 

 nally, the pericardium posteriorly, and the flancs and 

 branchial chamber externally, is occupied by the orange 

 ovaries (Fig. 100, h), which run forwards and outwards 

 along the sides of the stomach, to the anterior margin of 

 the carapace, and then backwards and outwards, along the 

 carapace, as far as the bases of its large lateral horns. 

 The character and size of the ovary varies considerably 

 according to the season, and in the late summer months, 

 after nearly all the eggs have been laid, it is usually much 

 smaller than it is shown in the figure, which was drawn 

 from a specimen which was caught in the winter. 



J). A branch (i) of the liver also takes nearly the same 

 course, and runs outwards along the side of the stomach 

 and the anterior edge of the carapace. It is below the 

 ovary, but as it is a little wider, the inner or free ends of 

 the lobules into which it is divided are visible between the 

 ovary and the bases of the gills. 



q. Make a drawing showing all these organs, in place, 

 as seen in a surface view. 



r. The heart. Cut open the pericardium and expose 

 the heart (^) in place. It is a white, fleshy, somewhat 

 hexagonal organ, which lies in the cavity of the pericar- 

 dium, to the walls of which it is loosely attached. Near 



