59. arius. 173 



process is one-third of the total length (with the caudal); basal bone 

 of the dorsal spine small. The teeth on the palate form two separate 

 subovate patches. The maxillary barbel extends to, or nearly to, the 

 middle of the pectoral fin. Adipose fin small. 



Cayenne. 

 a-b. Presented by Professor R. Owen. 



These specimens having had the cavity of the mouth and of the 

 gills extended in an extraordinary manner, I was induced to exam- 

 ine the cause of it, when, to my great surprise, I found them filled 

 with about twenty eggs, rather larger than an ordinary pea, perfectly 

 uninjured, and with the embryos in a forward state of development. 



The specimens are males, from 6 to 7 inches long, and in each the 

 stomach was almost empty. 



Although the eggs might have been put into the mouth of the fish 

 by their captor, this does not appear probable. On the other hand, 

 it is a well-known fact that the American Siluroids take care of their 

 progeny in various ways ; and I have no doubt that in this species 

 and in its allies the males carry the eggs in their mouth, depositing 

 them in places of safety, and removing them when they fear the 

 approach of danger or disturbance. 



64. Arius variojosus. 



Arius variolosus, Cuv. fy Val. xv. p. 107. 



D. 1/6. A. 22-23. 

 The distance between the end of the snout and that of the occipital 

 process is a little less than one-third of the total length (with the 

 caudal); basal bone of the dorsal spine small. The teeth on the 

 palate form two separate patches. The soft parts of the head with 

 numerous small round grooves. The maxillary barbels extend to the 

 end of the pectoral. Adipose fin small. ( Val.) 

 Cayenne. 



6S. Arius multiradiatus. 



Bagrus (?) arioides, Kner, Sitzgsber. Akad. Wiss. Munch. 1863, p. 227. 

 D. 1/7. A. 27. 

 The height of the body is contained five times and three-fourths 

 in the total length (with the caudal), the length of the head four 

 times. (Kner.) 



Rio Bayano (Panama). 



66. Arius equestris. 

 Arius equestris, Baird $ Girard, Proc.Ac.Nat.Sc.Philad.1855, p. 26, 

 and Ichth. U. S. &■ Mex. Bound, p. 32. pi. 15. 



D. 1/7. A. 16. P. 1/9 

 Maxillary barbels extending to the middle of the pectorals. The 

 length of the head is contained four times and three-quarters in the 



