GILBERT AND STAUKS — FISHES OF PANAMA BAY 139 



the upper. Pectorals short and broad, if to if in head, the upper angle rounded, not reaching as far 

 back as the ventrals, which equal them in length. Axillary scales of ventrals and pectorals very little 

 developed. 



Color varying from uniform deep bronze-purple on body and fins, to brownish gray with 

 silvery reflections. Lower parts of head and body somewhat lighter. Tip of mandible white. 



Ten specimens, the longest 189 mm., were taken around San Jose Rock, in 

 the Bay of Panama. 



In this species, three slender interneurals, not connected with dorsal spines, 

 lie in advance of the neural spine of the second vertebra. Four interneurals giving 

 attachment to dorsal spines, lie crowded between the neural spines of the second and 

 third vertebrte, the anterior one being very broad. Three interneurals follow, inter- 

 posed between the third and fourth neurals, and three more between the fourth and 

 fifth. 



Family CIRRHITID^. 



260. Cirrhites rivulatus Valenciennes. 



The only Panama record for this species is that by Gunther (1868, p. 421), 

 based on a specimen secured by Captain Dow. It was not seen by us. 



Family POMACENTRID.E. 

 261. Chromis atrilobatus Gill. 



Plate XXI, Fig. 43. 



This si:)ecies is very abundant about the islands in Panama Bay, where 

 numerous specimens were secured. 



It is a strikingly elegant fish in form and color. The upper parts are brown- 

 ish, shading to silvery on lower sides of head and trunk. The yellowish silvery 

 blotch at base of last dorsal rays and on the contiguous portion of the back is very 

 conspicuous. A jet-black bar, wider in its upper portion, crosses base of pectoral fin 

 and involves its axil. It often fails to reach the lower rays of the fin. The pectoral 

 fin is translucent, unmarked. The ventrals are translucent or slightly dusky. The 

 anal is light or variously dark, but is without distinctive markings. The spinous 

 dorsal is uniformly dusky, the anterior two-thirds of the soft dorsal, including the ray 

 which forms the tip of the lobe, jet-black, with a narrow white margin. The last 

 three or four dorsal rays are translucent. The outer half of each caudal lobe is jet- 

 black, with a narrow translucent margin, the entire central portion of the fin trans- 

 lucent. 



The body is slender, tapering regularly backward from the front of dorsal. 

 The top of head is everywhere transversely convex. The longitudinal contour shows 

 a slight but well-defined depression above the eyes. The teeth are in wide bands in 

 each jaw, the outer series conical, stronger than the others. The spinous dorsal is 

 rather low and of nearly uniform height. The soft dorsal and anal are distinctly 



