FISHES OF THE FAMILY LORICARIID. 307 
Subfamily V. ARGIIN&. 
Vertebrz below the dorsal fin with bifid neural spines; those above the anal with 
bifid hemal spines; lower and fourth upper pharyngeals toothed; teeth in the jaws 
in more than one series; no pseudobranchie ; body naked ; anterior rudimentary ray 
of ventral represented by a small internal rounded plate. 
The Argiine are to be regarded as degraded or ultra-specialised forms closely 
related to the Neoplecostomine, from which they differ mainly in the naked' body and 
the stronger ribs. he structure of the adipose fin, which is in some species composed 
of a well-developed movable spine, attached posteriorly by a membrane to the caudal 
peduncle, is sufficient evidence that the nakedness of the body is a secondary and not a 
primitive feature. The neural and hemal spines are somewhat less expanded than in 
the other subfamilies, whilst there is also a slight difference in the structure of the 
suspensory apparatus, the pterygoid being small, instead of large and connected with 
the prefrontal, as in the armoured forms. ‘The clavicles and coracoids run somewhat 
forwards to their symphysis, whilst in the other subfamilies their lower portions lie 
transversely between the bases of the pectorals. 
Key to the Genera. 
Wentralifinsipresenbmecn =. 2 2) (ime sel oe ste ean tle ehOsmear- eel Caen 
Wentralifins}abserntamer ars -icul cis) Wein cule) ira ius, uae ean as eienen Veued| Shr-oulenuseliam bs 
16. ARGEs. 
Cyclopium* Swainson, Nat. Hist. Fishes, ii. 305 (1839) ; Eigenm. & Eigenm. Proc. Cal. Ac. (2) 
1. 1888, p. 164, and Oce. Pap. Cal. Ac. 1. 1890, p. 350. 
Arges Cuv. & Val. Hist. Nat. Poiss. xv. p. 340 (1840) ; Giinth. Cat. Fish. v. p. 222 (1864). 
Brontes Cuv. & Val. t. c. p. 341; Giinth. t. c. p. 224. 
Stygogenes Giinth. t.c. p. 223. 
Body oblong or elongate; eyes small, superior. Dorsal originating above or a little 
in front of or behind the ventrals, with I 6 rays; anal with I 5-6; pectoral with 
J 9-12; ventral with I 5-4. Caudal truncate or slightly emarginate, with the outer 
rays a little produced. Adipose fin *, if present, either represented by a movable 
spine, posteriorly attached by a membrane to the caudal peduncle, or by a long more 
or less developed fin, with or without a small or rudimentary imbedded spine. 
Vertebre 5+12+17 (in A. feste). Ribs fairly strong. 
Andes of Peru, Ecuador, Colombia, and Venezuela. 
‘ Swainson established the genus in these words :—‘ The third genus is that by which we distinguish the 
Pimelodus cyclopium of Humboldt (Cyclopium humboldti Sw.).” His generic name, being derived from 
the genitive plural of Cyclops, is as inadmissible as would be that of Silurorum. 
2 Those who regard the adipose fin as a primitive feature, perhaps inherited from a common ancestor by the 
Siluride and other Fishes possessing it, should note how in the genus Aryes a modified and reduced adipose 
fin like that of the armoured Loricariidw becomes replaced by a long and well-developed fin exactly similar to 
that of a Pimelodus. 
