49 

 Genus Zungaro Bleeker. 



SYNONYMY. 



Zungaro Bleeker, Ichthyologifp Archipelagi Indici Prodromus, vol. 

 I. Siluri, p. 169, 204. 



Branchiostegal membrane "with only four rays on each side. 

 Ventral fins with one simple and nine branched rays. Dorsal and 

 pectoral spines slender, concealed in the membrane. 



This genus was founded on the Pimelodus zungaro of Humboldt. 

 It is possible that the great physicist has overlooked one or two 

 branchiostegal rays. He has asserted that none of the fins have 

 spines ; but, as Valenciennes has suggested, they are probably present 

 in the dorsal and pectoral fins as usual, but enveloped in a thick 

 membrane. "We have not been able to examine Humboldt's original 

 memoir, but as the species is described by Valenciennes as recalling 

 the form of the Pimelodus hufonius (or Pseudopimelodus hufonius), 

 and to differ only in the characters above enumerated, there is little 

 doubt that the diagnosis of the section in which it is placed is equally 

 applicable to it and Pseudopimelodus. One species is known. 



Type Zungaro Humboldtii Bleeker. 



Syn. Pimelodus zungaro Humholdt. 



It is an inhabitant of the upper Maranon in the Province of Jaen 

 de Bracamoros, where the cold streams descending from the Cordil- 

 leras enter that river. 



Group IcTALURi Gill. 

 Supramaxillary, nasal, and two pair of inframaxillary barbels 

 always present. Anal fin longer than high, conmienciug near the 

 anus. 



Genus Ictalurus (Raf) Gill. 



SYNONYMY. 



Silurus sp. Raf. 



Pimelodus sp. Raf. Ichthyologia Ohiensis. 



Ictalurus sp. Raf. Ichthyologia Ohiensis. 



Elliops sp. Ptaf. Ichthyologia Ohiensis, p. 62. 



Pimelodus sp. KirUand. auct. 



Synechoglanis Gill Annals of Lvceum of Natural History of New- 

 York. 



Type Ictalurus coerulescens Gill. 



Syn. Pimelodus coerulescens Raf 



Body slender and anteriorly subcylindrical. Head obliquely com- 

 pressed, small, covered with a thin skin. Supraoccipital bone posteri- 

 orly cleft and receiving the acuminate anterior end of the head of the 

 second interspinal. Mouth moderate or rather small ; seven to nine 

 branchiostegal rays on each side. Anterior dorsal fin with a stout 



PROCEEDINGS B. S. N. H.— VOL. Vlll. 4 APRIL, 1861. 



