NATURAL SCIENCES OP PHILADELPHIA. 257 



years of the present century, although it was considered as the type of a pe- 

 culiar genus by Gronovius as early as the year 1763. That erudite and 

 sagacious ichthyologist accepted for it a name given by Klein to a heterogenous 

 group, of which the species in question was one. It is therefore expedient to 

 examine the group of Klein, more especially 'as his name has been employed 

 for widely distinct genera. 



It was in his fourth "Missus," and in the year 1744, that Klein intro- 

 duced into the literature of the science the name Enchelyopus. He bestowed 

 this name (s^xst/a^v) on fishes which he supposed to be analagous to, or 

 "collateral" with, the true eels, but distinguished by their open or ample 

 branchial apertures. To them were likewise attributed oblong, smooth oper- 

 cula, of the consistency of more or less tough parchment, and readily com- 

 pressible, and more or less elongated and cylindrical bodies. The species 

 were distributed among two divisions, those with an elongated dorsal, and 

 those with a short one. The character of the genus Enchelyopus may be best 

 learned by a knowledge of its contents. Those indicated iy an asterisk (*) 

 after the number of the species, are figured in Klein's work. 



I. Enchelyopfjs pinna dorsali longa. 

 l.*Lepturus argenteus Gill ex Shaw. 



2. Lepturus haumela Gill ex Forsk. 



3. Lepturus. 



4. Ophidion barbatum L. 



5. Ammodytes tobianus L- 

 6.*Hyperoplus lanceolatus Gill ex Les. 



7. Trachypterus iris C. et V. 



8. Trachypterus taenia. 



9. Trachypterus taenia BL, Schn. 

 10. Cepola rubescens L. 

 ll.*Enchelyopus viviparus Gronov. 

 12.*Lota vulgaris Cuv. 



13. " " 



14. Molva vulgaris Flem. 



15. Mastacembelus. 



16. Rhynchobdella aculeata Gthr. ex Block. 



17. Geinpylus serpens Cuv. 



II. Enchelyopus pinna dorsali brevi. 



1. Misgurnus fossilis Lac. 

 2.* " * " 



3.*Nemachilus barbatula Blkr. 

 4. Cobitis taenia L. 

 5.*Gobio fiuviatilis Aq. 



It is not necessary to remind the ichthyologist who analyzes this genus of 

 Klein, that it would be almost impossible to combine together as many spe- 

 cies which should offer more numerous points of difference than the fishes 

 thus associated. Representatives of eleven families,* most of which have little 

 affinity to each, are thrown together in one heterogenous mass ; nor is the 

 group confined even within the limits of the vague diagnosis, for, although 

 none of its members have the branchial aperture as restricted as the eels, still 

 there is quite a wide difference in their extent between some of the species, 

 such as the Cobitoidae contrasted with the Lepturoids. Although it may not 

 be allowable to criticize the fathers of science as if they had enjoyed the bene- 

 fits of that knowledge which is the slow result of a century of labor, it will 



* Lepturoidae (1, 2, 3.) Ophidioida; (4.) Arurnodytoidse (5, 6.) Trachypteroidie (7,8,9.) Ccjioloidse 

 (10.) Lycodoidse (11.) Gadoidas (12, 13, 14.) Mastacerubeloidao (15, 16.) Scombroids (17\ Cobitoida? 

 I II. 1, 2, 3, 4). Cyprinoidffi (5). 



1863.] 



