146 HYATT, 



inof, however, in having cells with contents of a lighter 



C ' O O 



color, 



My observations with regard to the universality of the 

 transverse striae are confirmed by Hancock, who found 

 them in both the stomach and oesophagus ; whereas All- 

 inau, in the sentence just quoted, thinks that they are absent 

 in the latter and in the walls of the intestine. 



The digestive canal is simpler than in many of the low- 

 er polyzoa ; it has neither the crop of Laguncula, or the 

 ccecal appendages of Flustra, and is without special organs 

 of secretion, except in so far as their places may be supplied 

 by the cells of the first membrane. 



The oesophagus is an open cylindrical cavity, invaria- 

 bly shorter and narrower than the stomach, the lower por- 

 tion somewhat enlarged, the oral or upper part funnel 

 shaped and ciliated (PL 7, fig. 5, PL 11, fig. 1, PL 12, 

 fig. 1, K) . The stomach may be typically considered as a 

 single tubular cavity Avith an anterior flexure near the 

 pyloric end, and the anterior side of this flexure prolonged 

 into a gourd-like ccecum of great size and length (PL 7, 

 fig. 5, PL 11, fig. 1, PL 12, fig. 1 K'). 



The intestine varies more in form than either the 

 oesophagus or stomach, but is universally broad below and 

 tapering towards the anus (PL 7, fig. 5, PL 11, fig. 1, 

 PL 12, fig. 1, K"). 



Two valves intercept free communication between the 

 gastric cavity, and the oesophagus, and intestine (PL 7, 

 fig. 5, PL 11, fig. 1, PL 12, fig. 1, K'", K""). 



The first of these, the cardiac, or QEsophagal Valve, is a 

 perforated coniform projection of the walls of the canal at 

 the point of union between the oesophagus and stomach. 

 The longer part being within the cavity of the stomach, 

 and the apex directed anteriorly, it is usually sufficiently 

 strong to 1 prevent the regurgitation of the food. The 

 second, the pyloric, or Intestinal Valve, has a similar struc- 

 ture, but is not so thick, and forms a flat partition between 

 the two compartments. 



The reception and elimination of nutritious material 

 by this simple apparatus is among the most striking of 

 the phenomena exhibited in the structure of these animals. 



