PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 65 



was taken at Unalaslika, September 13, 1873, iu 50 or 60 fathoms. Mr. 

 3)all informed me that Dr. Steindachner saw it in San Francisco, and 

 considered it identical with the Hippoglossus viih/aris. I have compared 

 it carefully with Atlantic halibut from Eastport, Me., and fail to see 

 any means of separating the two. The Alaska individuals are a little 

 thicker ; but that may be accounted for by the differences in the food 

 supply. It is very desirable to have perfect specimens of the Pacific 

 fish for examination ; but, in the absence of such material, I have en- 

 deavored to make the most of what the museum has, and it is believed 

 that the table of measurements will serve to confirm the views of those 

 who regard the halibut of the Pacific identical with that of the Atlantic. 



DESCRIPTION OF THE UNALASHKA SPECLIVIEN. 



The museum catalogue number is 224G6, and the collector's number 

 1098. The length of the fish to the origin of the middle caudal rays is 

 463 millimetres. The different proj)ortions of the body are given in 

 hundredths of this length. 



The greatest height of the body (.32) is 4 times the length of the oper- 

 culum (.08) ; its height at the ventrals (.25) is contained 4 times in the 

 total length, and equals the distance of the pectoral from the snout 

 (.25). The least height of the tail (.07i) is nearly equal to the length of 

 the operculum (.08), and to the distance of the dorsal from the snout 

 (.08). The length of the caudal peduncle (.12) equals that of the longest 

 anal ray (.12). The lateral line follows the same course as in Eastern 

 specimens. 



The greatest length of the head (.25^) is contained nearly 4 times iu 

 the total length. The distance between the eyes (.03) equals ^ the dis- 

 tance from the snout to the orbit (.06). The length of the snout (.04^) 

 equals almost ^ the length of the upper jaw (.09^). The length of the 

 upper jaw is not quite equal to that of the pectoral of the blind side 

 (.10). The maxilla extends to the vertical through the middle of the 

 lower eye. 



The length of the mandible (.Hi) is contained 2^^ times in the length 

 of the head. It extends to the vertical through the posterior margin 

 of the lower eye. 



The long diameter of the upper eye (.05) is contained 5 times in the 

 length of the head, and twice in that of the pectoral of the blind side. 

 The teeth agree perfectly in all respects with those of the Eastport in- 

 dividuals, that is, they are arranged in two series in the upper jaw, the 

 outer being the stronger, and in a single series in the lower jaw. 



The distance of the dorsal from the snout (.08) equals the length of 

 the operculum. Its longest ray (.11^) does not quite equal the longest 

 of the anal (.12). The 37th and 38th dorsal rays arc the longest. 



The distance of the anal from the snout (.34) equals ^ of the head's 

 length. Its longest ray, the 17tli, (.12) is contained 8J tunes in the total 

 length. 



Proc. Nat. Mus. 79 5 July 1 , 1 H 79. 



