PEEOPHOEA. 157 



external surface of the primary vessels exhibits a few 

 dots, probably indicative of the branchial suspenders, 

 and there is some appearance of transverse ribbon- 

 like membranes, similar to those in Glavelina, project- 

 ing: into the cavity of the or'an, from these same 



O (/ O 



vessels. 



The endostyle is broad, with the ends obtuse. It 

 extends some way above the upper margin of the bran- 

 chial sac, and it reaches below to the bottom of this 

 organ, the posterior end being a little bent forward or 

 inward. The anterior cord is wider than usual. 



[Dr. Lister states that the heart is placed " near the 

 bottom of the branchial sac on the left side (fig. 86), 

 and consists of a transparent ventricle . . . running- 

 forward and a little sloping downward in a channel 

 hollowed to contain it."] The two vessels proceeding 

 from the heart to the stoloniferous stem are easily 

 observed in their course through the peduncle. They 

 are seen as if originating in the great dorsal, branchial 

 channel, though undoubtedly only one of them so 

 originates. 



The digestive organs are placed for the most part 

 on the right side (fig. 85) of the branchial sac, the 

 oesophagus and much of the stomach, however, lie 

 below it at the bottom of the pallial chamber. 



The mouth opens through the lower extremity of 

 the branchial sac, close to the ventral margin. The 

 oesophagus, which is a narrow tube of some length, 

 dips downwards and backwards in an even curve to 

 its union with the ventral end of the stomach. This 

 latter viscus is an ovate bulb, lying transversely at the 

 bottom of the pallial chamber, the narrow or dorsal 

 extremity of which graduates into the intestine. 



The intestine is wide, and passes backwards as far 

 as the endostyle, and then, arching upwards, shortly 

 turns towards the ventral side, at this point being 

 somewhat enlarged; dipping downwards and forwards 

 it ascends a little to reach the cloaca, where it termi- 

 nates in a rather wide anal orifice. The intestinal 



