l8o PATTEN AND REDENBAUGH. [Vol. XVI. 



them together with the operculum, among the abdominal append- 

 ages. For example : (i) a bar of capsuliginous cartilage (b.cJ) 

 acts as an internal support for the appendage, and this bar is 

 identical in structure with the branchial bars found in the 

 operculum and gills. The fact that this capsuliginous cartilage 

 is found only in the branchial bars of the chilaria, operculum, 

 and gills renders the resemblance the more striking. (2) The 

 roof of the occipital ring (per.) is very similar to the abdominal 

 endochondrites {a.e.^~'^). (3) The chilarial muscles (7'^) arising 

 from the neural side of the occipital ring and inserted upon 

 the insides of the chilaria may be compared to the internal bran- 

 chial muscles {i.b.niP-'^) ; and, the long tergo-coxal muscle (/-^) of 

 the chilaria resembles the external branchial muscles (e.b.m.^~'^). 

 (4) Its neural and haemal nerves are more like those in the 

 abdomen than those of the thorax. 



If we regard the chilarial and opercular neuromeres as ab- 

 dominal rather than cranial, and consider that the anterior parts 

 of the intestine and probably of the heart are innervated from 

 the sixth, seventh, and eighth neuromeres, then the intestine 

 and the heart must be mainly abdominal organs, indicating a 

 greater forward movement of the organs in the haemal than on 

 the neural side of the body. 



II. The innervation of the liver, nephridia, and generative 

 organs has not been made out. 



Wm. a. Redenbaugh. 



