300 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



It agrees with Aheona minima in the peculiar dentition characteristic 

 of that genus, as well as in the large scales and shortened tins. Its 

 form is, however, quite different, resembling more the genera Bracliyis- 

 tills and Cijmatogaster. It is a considerably larger fish than Abcona mi- 

 nima; its dorsal spines are weaker and the number of fin rays is greater. 



(D. IX, 14 ; A. Ill, 16 — in Abcona minima.) 



From Cijmatogaster aggregatus it is widely separated by the different 

 dentition; with Brackyistius frenatus Gill it has closer affinities, but the 

 two species belong to different genera. 



This latter species has been but once observed, and no descrij^tion 

 has been yet published, merely a brief note enumerating some of its 

 peculiarities. We therefore subjoin a fuller account, drawn from a fine 

 specimen obtained by us at Santa Barbara. 



Brachyistius frenatus Gill.* 



(Proc. Acad. Nat. Sci. Phila., 1862, 275.) 



Body elongate, compressed, the body proper regularly elliptical, with 

 long caudal peduncle.. Head long, very slender and pointed, much de- 

 I)ressed above the eyes, the snout projecting. Mouth very small, ter- 

 minal oblique, the small maxillary falling much short of the orbit. Lips 

 rather thin, the lower with a frenum. Teeth loug and slender, some- 

 what lanceolate, few in number, arranged in a single series. 



Preorbital broad. Cheeks with about two rows of scales; opercles 

 with three. Eye large, anterior, about 3 in head. 



Gill-rakers numerous, long and slender. 



Scales large, 42 in the course of the lateral line. Dorsal spines high 

 and rather strong, the first low, the others rapidly increasing to the sixth 

 and seventh, the eighth shorter, the soft rays a little higher than the 

 highest spines. 



Caudal peduncle nearly as long as the head, not very slender. Caudal 

 fin rather deeply forked. 



Anal spines feeble, the fin elevated in front. Ventrals reaching soft 

 rays of anal. Pectorals reaching first anal spine. Ventral groove very 

 short. 



D. VlIT, 15; A. 111,23. 



Color dark olive-brown above, with lighter stripes along the rows of 

 scales. Below every where a brilliant light coppery red; each scale with 

 a light blue spot and dark punctulations. Head colored like the body. 

 Fins all light reddish, plain, the dorsal somewhat dusky. A streak of 

 sky-blue si)ots below and in front of the eye. 



Measurements of Aheona aurora. 



Extreme lengtli 6. 93 inches 



Length to base of caudal 5. 57 inches = 100 



* We have since obtained this species in very great numbers at various places along 

 tlie coast from Los Angeles to Vancouver's Island. Ditrema brev'qnnne Giinther is 

 undoubtedly the same Bj)ecies. 



