REPORT ON THE DEEP-SEA FISHES. 21 



Hoplostethus mediterraneum. 



Hoplostethus mediterraneus, Cuv. et Val., iv. p. 469, pi. xcvii., his. 

 „ „ Guichen, Explor. Alger, poiss., p. 42. 



» ,. Giinth., Fish., vol. i. p. 9 ; Anu and Mag. Nat. Hist., 1878, vol. i p 



485. 

 „ „ Jordan and Gilbert, Synopsis, p. 458. 



„ „ Steindachner, Denkschr. d. k. Akad. d. Wiss. Wien, 1883, xlvii. p. 



218, tab. i. 

 Trachichthys pretiosna, Lowe, Proc. Zool. See. Lond., 1839, p. 77; Fish. Madeira, p. 55, pi. ix. 

 Hoplostethus japonicus, Hilgeudorf, Sitzungsb. d. Gesellsch. naturf. Freunde, Berlin, 1879, 



p. 78. 



D. ^^. A. f. V. i. L. lat. 28-29. Vert, fi- 



Specimens of this species have been discovered at distant intervals of time at 

 considerable depth (the precise depth is not known) in the western parts of the 

 Mediterranean, off Madeira, and recently also in the Sea of Japan. Dr. Hiloendorf 

 was of opinion that he could specifically distinguish Japanese specimens by a somewhat 

 larger number of abdominal scutes. This would have been a character insignificant 

 enough, even if the Japanese specimens had not sometimes the same number of scutes 

 as the Mediterranean. A more important difference seems to be the structure of the 

 scales, which I find in Japanese specimens, on the whole, less strongly ctenoid than 

 in Madeiran. But even in this respect there is no constancy in specimens from either 

 of the two localities. 



A specimen 3 inches long has lately been dredged by the U.S. Fish Commission, 

 off Chesapeake Bay. 



Trachichthys, Shaw. 



Body compressed, more or less deep, covered with small ctenoid and generally rough 

 scales, which are rather irregularly arranged. Abdomen protected by dermal scutes, 

 which form a serrated edge. Head very large, the superficial bones being deeply 

 sculptured to receive wide muciferous cavities which are covered by thin skin only. 

 Mouth very wide, oblique ; villiform teeth in the jaws and on the vomer and palatine 

 bones. Eighty branchiostegals ; gill-openings very wide, gill-laminaj very short. Supra- 

 scapulary and angle of the prseoperculum armed with a spine each. One dorsal fin, the 

 anterior rays of which are spinous ; ventrals with six soft rays ; pectoral symmetrical ; 

 caudal deeply forked. 



Lowe is right in stating that Hoplostethus is scarcely entitled to generic rank, the 

 whole difference between it and Trachichthys being the absence or presence of vomerine 

 teeth. The structure of the bones of the head, the development of large muciferous 

 cavities, the large eye, the more or less intense black colour of the pharyngeal and 

 branchial cavities, and finally the mode of occurrence, clearly indicate that the species of 



C 



