183 PROCEEDINGS OF THE ACADEMY OP 



whose relations and differential characters are expressed in the following 

 table : 



I. Head acutely conic ; snout pointed, and oral cleft nearly recti- 



linear. Teeth of lower jaw part enlarged, slender and pointed, 



part small and slender Paralepis. 



a. Dorsal fin decidedly in front of ventrals Arctozenus. 



p. Dorsal fins opposed to ventrals Paralepis. 



II. Head blunt, and oral cleft curved upwards towards the end. 



Teeth of lower jaw partially erect, compressed, dagger-shaped, 



partially directed forwards Scdis. 



The distribution of these three groups is most remarkable. Paralepis and 

 Sudis are types as yet only known to be represented in the Meditteranean 

 Sea, while Arctozenus is represented by a single species, hitherto only fouod in 

 the waters of Greenland, and yet there is the closest affinity between Paralepis 

 and the Arctic type, so close, indeed, that only since the opportunity afforded 

 to examine the detailed figures of Kroyer, have we been able to fully appreci- 

 ate their distinctive characters. In order to assist less fortunate naturalists, 

 the following diagnosis of the newly named subgenus is given. 



ARCTOZENUS, Gill. 



Head elongated conical, attenuated towards the snout, with the snout ^ap- 

 pointed, the jaws straight, the lower behind mostly covered by the upper, and 

 little exposed along the sides ; the teeth of the lower jaw, along the anterior 

 half, enlarged, but slender, recurved and distant ; along the posterior half, 

 minute, acute and approximated ; the dorsal fin behind the middle, but con- 

 siderably in front of the ventrals. 



Type. Paralepis borealis, Reinh. 



In the family of Microstomatoids,* which is related to the Paralepidoids, we 

 find the same peculiarity in geographical distribution ; the genus JUierostomaf 

 being confined to the Mediterranean, while in the Greenland seaB a closely re- 

 lated representative is found. 



Still another case of similar, or rather even more remarkable character, is 

 exhibited by the Stomiadoids. This family, distinguished by the com- 

 bination of an enormous mouth, and the opposition of the dorsal and 

 anal fins, is composed of two genera, Stomias and Malacosteus. The former 

 is represented by apparently closely related species, respectively inhabiting the 

 Mediterranean and Greenland Seas, while of Malacosteus, a single species dis- 

 covered south of the Newfoundland Bank has been described. As, on account 

 of the misconceptions of the author of the last named genus, it has been in- 

 volved in considerable mystery, a diagnosis of it, with reference to its ally, 

 may be useful ; but I desire expressly to add, that I do not hold myself respon- 

 sible for any of the facts, not having seen the original specimen, and that the 

 statement of the absence of scales, &c, requires to be confirmed, although it 

 is quite probable that none exist. The original describer has denied to the 

 genus branchiostegal rays ! 



MALACOSTEUS, Ayres. 



Proc. Boston Nat. Hist. Soc. Boston Journ. N. H. vi., 53 64. 



Body elongated claviform, constricted only at the caudal peduncle ; without 

 scalis ; with the head very convex, and protuberant in front of the eyes; the 

 opercular and tympanic regions very oblique, the opercular bones reduced, the 



* Although the adipose fin has been denied to Microstoma by such skilful observers as Muller 

 and Valenciennes, I think that I am able to distinguish it in specimens of the M. rotundatum, 

 preserved in the collection of the Academy. 



t Microstoma, Cuv., R. A. 1817, ii., 181 : Risso, 1829, ii. ; Cuv. et Yal. xviii., 358. Bernhardt ap- 

 pears to have first introduced the modification Microstomas. 



[Sept. 



