KEPOKT OX ICHTUYOLOGY. 425 



IIOPLADELUS, (Raf.) Gill. 

 Synonymy. 



Glanis liaf. MSS. Amorican Monthly Magazine an 1 Critical Kcvicw, vol. iv. 



LKl'TOrs Raf. Icbtliyologia Ohionsis, p. 04. 



Oi'LADEi.us Riif. Iclitliyologia Ohieusis, p. fit. 



Ilictis Eaf. Icbtliyologia OUienais, p. 6(1. 



PYLonicTis Raf. Ichtbyologia Obiensis, p. 67. 



ICTALUKUS sp. Raf. 



PiMELODUS sp. Kirtland, auct. 



Tlie body is much elongated, and presents in i:)rofde a very slender appearance. It 

 •is much depressed, and is anteriorly broader than high. 



The head is large, very wide and depressed, laterally expanded, above broadly 

 ovate, and in profile enneiform. The skin is very thick and entirely conceals the skull. 

 The supra-occipital bone is entirely free from the head of the second interspinal. 



The eyes are small. 



The mouth is large, anterior, and transverse. The lower jaw projects beyond the 

 upper. 



The teeth are in broad villiform bands on the iutermaxillaries and dentaries. Tlie 

 intermaxillary band, is convex anteriorly, and proceeds to the insertion of the maxil- 

 laries, where it is abruptly angularly deflected, and proceeds backward as elongated 

 triangular extension. The band at the symphysis is slightly divided, and anteriorly 

 separated by a small triangular extension of the labial membrane. The lower dental 

 band is anteriorly semi-circular, and attenuated to the corners of tlie mouth. 



There are about, twelve branchiostegal rays on each side. 



The doi'sal fin is situated over the posterior half of the interval between the pec- 

 torals and ventrals, and has a spine and about seven branched rays. 



The adipose fin is Avell developed, and has an elongated base resting over the 

 posterior half of the anal; it is very obese, and inclines rapidly backward. 



The anal fin commences far behind the anus, is little longer than high, and com- 

 posed of about fifteen rays. 



The caudal fin is oblong, subtruncatcd, placed on a vertical Ijasis, and with 

 numerous accessory, simple rays, recurrent above and beneath the caudal peduncle. 



The pectorals have a broad, compressed spine, serrated or dentated on its external 

 and internal margins, and with the prolonged fleshy integument obliquely striated. 



The ventrals are rounded, and have nine rays, one simple and eight branched. 



The anus is situated behind the ventrals, some distance behind their bases, and 

 much in advance of the anal fin. 



The genus Hopladelus is at first sight distinguished by its elongated and anteriorly- 

 depressed body; the depressed and broad oblong head; the bands of very small 

 villiform teeth, and the posterior extension of the up[)er b.ands; the small size of the 

 anal, its distance behind the anus, and the recurrence of the caudal fin. 



But one species is certainly known. 

 54 B u 



