390 



PROCEEDINGS OF THE CANADIAN INSTITUTE. 



From the coecum a fold of the left portion of the mesentery passes 

 to the larger loops of the midgut. 



The air-bladder is covered by a peritoneal plate arising from the 

 lateral walls of the body cavity and meeting in the middle line. To 

 the walls of the air-bladder it is less closely applied than elsewhere. 



Larce pellets of fat are distributed in the mesentery, most 

 frequently in the fold connecting the coecum and midgut. 



The mesentery is not always continuous, there frequently appear- 

 ing in it large, clear spaces, the positions of which are, however, 

 irregular. 



The following table of measurements of the intestinal tract, in- 

 cludes those of one specimen of A. catus and two of A. nigricans. 

 The length of the body, as here given, is from the termination of 

 the snout to the base of the caudal fin. It will be seen from 

 examination that the lengths of the same parts in the three are not 

 relatively proportional. For instance, in A. catus the length of the 

 midgut is 1*25 times that of the body, while in the smaller specimen 

 of A. nigricans it is 1-14, and in the larger T8. In the numerous 

 measurements that I have made of the intestinal tract of cat-fishes 

 of various sizes, it was observed that with the increase in body 

 length there is more than a corresponding increase in the various 

 parts, and especially so in the midgut. The whole intestine also 

 from the commencement of the oesophagus to the vent varies from 

 15 to 2-3 times the length of the body. 





^ . 



W o 

 -S f0 



< 

 o 



§ 



Stomach 

 (Cardia and 

 Coecum). 



3 



a 



c 



O-i 



MlDOUT. 



Endgut. 



o 



>< 

 a 

 o 



n 



a 

 a 

 a 

 a 

 < 



M 



« 



< 





c. 



c. 



| 















31 



38 



3-5 

 22 



3 



2 



2 

 1-5 



40 

 32 



5 

 4-8 



10 



7-5 



5-5- 



A. nigricans (1). . . . 



3-8 



A. nigricans (2). . . . 



60 



5 



6 



3 



110 



9 



— 



— 



FINE ANATOMY. 

 MOUTH AND PHARYNX. 



The mucous membranes of the mouth and pharynx are exceedingly 

 .similar in structure, so that the following description applies justly 



