NATURAL SCIENCES OF PHILADELPHIA. 2G5 



Head oblong, with the snout produced, oblong, gradually narrowed, and 

 with its periphery convex. Eyes moderate, with the pupil vertical. Nostrils 

 nearer the front of the rcouth than the snout, nearly rectangular to mouth, 

 with the anterior flap small and near the inner angle. 



Mouth moderate, but convex in front, and wider than deep. 



Teeth of upper and lower jaws dissimilar; of each jaw mostly similar, but 

 smaller and more oblique towards the corners of the mouth ; two symmetrical 

 front. ones iu upper, an unpaired one in lower jaw; the two front teeth of the 

 upper jaw inclined towards each other ; the rest serrated, oblique, rectilinear or 

 nearly so along the inner edge, and with an obtusely angled emargination at the 

 outer edge, the lower branch of which forms the so-called heel. Lower jaw 

 with a small azygous erect tooth at symphisis; the rest with broad bases and 

 narrow oblique entire or weakly crenulated cusps, inclining more as they re- 

 cede from the symphisis. 



Branchial apertures moderate; the fourth, typically, nearly above the outer 

 base of the pectoral fin. 



Dorsal fins dissimilar ; the first nearly midway between the pectoral and 

 ventral fins, or little nearer the former, moderate, obtusely produced at the 

 anterior angle, and acutely prolonged at the posterior ; the second small, narrow, 

 produced acutely from the posterior angle. 



Anal fin nearly opposite the second dorsal, slightly larger than the latter, 

 obtusely enlarged at the anterior angle, acutely produced at the posterior. 



Caudal fin above with a pit at base, normally prolonged, and with a moderate 

 lower lobe, narrow towards its rounded apex. 



Pectoral fins moderate, but narrowed towards the rounded point, with the 

 inner angle little produced. 



Ventral fins moderate, rhomboidal. 



Type. Platypodon menisorrah Gill. 



Syn. Carcharias (Prionodon) menisorrah Mutter and Hcnlc. 



This genus was first named in the " Analytical Synopsis of the Order of 

 Squali," but no diagnosis was there given. Platypodon differs from Isoplagiodon 

 in the dissimilarity of the teeth of the two jaws, the two paired teeth of the 

 front jaw, and, perhaps, in the form of the mouth and narrower caudal portion 

 of the tail. Squalus tiburo Poey, S. acronotus P. and S. obscurus Les., belong 

 to it. 



Notes of an Examination of the Birds of the Subfamily COEBEBIN.E. 



BY JOHN CASSIN. 



1. Genus COEREBA, Vieillot. 



Coereba, Vieill., Ois. d'Am. Sept. ii. p. TO (1807). 

 Arbelorhina, Cab., Schomb. Reisen iii. p. 675 (1848). 



This name is now almost universally applied to the group for which I use 

 it in this paper, and of which the bird described by Linnaeus as Certhia cyanea 

 may be presumed to be the type. Vieillot, as above cited, evidently adopts 

 it as a name for a group which he regarde'd as a genus, intending to include 

 that species (C. cyanea) to which the name Guira-coereba Brasiliensibus had 

 been previously given by Marcgrave and Piso in Nat. Hist. Brasil, p. 212. It 

 was not the usage of Vieillot nor of numerous other binomial authors, inclu- 

 ding Linnaeus, to assume any one species as the type of a proposed or adopted 

 genus, and in my opinion there is a very considerable degree of impropriety, 

 as well as injustice, in ascribing to those authors any other than their real 

 and palpable intentions. For genera, the names of which are adopted from 

 other authors and the same groups intended to be designated, those authors, 

 whether ante- Linnsean or other non-binomia', (or any other,) ought to be con- 



1864.] 



