96 Evermavv avd Kewkill — Fkh from Central Ervadnr. 



includes the group in a sul^family Argiinie in the family Lori- 

 cariidas. 



The following list enumerates the characters which, according 

 to Regan, distinguish th(> subfamily Argiina3 from the other su))- 

 families of the Loricariida*, and which, as suggested hy Dr. Gill, 

 and according to our own view, are sufficient to establish a well 

 marked family : 



Teeth in jaws in more than one series ; no j)seudobranchia' ; 

 body naked, no l^ony plates or scutes ; rudimentary ray of 

 ventral present, representt'd b.y a small internal round plate ; 

 stronger ribs ; neural and ha3mal spines some\vliat less expanded; 

 pterj'goid small, instead of large and not connected with the 

 prefrontal ; clavicle and coracoids running somewhat forward 

 to their symphyses instead of the lower portions lying trans- 

 versely between the bases of the pectorals. 



In this suljfamily, as he regards it, Regan recognizes only one 

 genus, Arges, substituting Cuvier & Valenciennes's name for 

 Swainson's Gydopkvm for the folloAving reason which he gives 

 in a footnote on page o07 (1. c.) : 



Swainson established the genus in these words : "^The third genus is 

 that by which we distinguisli the Pirit/'lodus cydopum of Humboldt {Ci/clo- 

 p'min hiunholdlli Sw.)." His generic name being derived from the genitive 

 plural of Cyclopn, is as inadmissible as would be that of S'durorum. 



While most American zoologists regard as very objectionaljle 

 the use in generic nomenclature of the genitive plural form of 

 a substantive, they do not hesitate^ to accept sucli words when 

 once used, retaining the original spelling. Any other practice 

 tends away from stability of nomenclature. But ^^'hatever A'iew 

 one may hold regarding this matter, Mr. Regan's contention 

 does not hold in the case under consideration. Cydopium is 

 not the genitive plural of Cydops, as he imagines, but the neuter 

 form of the adjective cydopius. 



The only character that separates the genera Arges and Cydo- 

 pium is the presence of a spine in the location of the " adipose 

 fin " of the latter. That this spine may have been easily over- 

 looked in other specimens, since it is so often concealed under 

 the skin in ours, is evident. Bj^ an examination of specimens 

 of the species of Arges, it is possil)le that a spine may be found. 

 This character is therefore of doubtful value. 



Regarding Astrohlejms, it remains to be said that, for the same 



