PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 283 



expressly stated by Cuvier to be derived from dijja, blood, and duXov, 

 gums. 



The name Diahasis of Desmarest (1823) has priority over Hcemulon, 

 and has been substituted for the latter by Bennett, Bleeker, Jordan and 

 Gilbert and by others. This name is, how ever, preoccupied * in Coleoptera 

 by the genus JJiahasis, Hoffmansegg, 18] 9. There appears, therefore, to 

 be no doubt of the propriety of the retention of the name Hcemulon. 

 Hceitudon sciurus (Shaw) {elegans Cuvier), the first species mentioned by 

 Cuvier, may be regarded as the type of the genus. 



Twenty species of Hcemulon are recognized by us as probably valid. 

 These we group in five sections or subgenera of rather slight value, for 

 which we adopt the names Hcemulon^ Bathystoma, Brachygenys, Lytliru- 

 lon^ and Orthostoechus. Of these, Hcemulon contains most of the species, 

 and exhibits a greater range of variation than the others. 



The young fishes in this group differ in proportions considerably from 

 the adults. Besides the changes usual in other fishes we may observe 

 that in Hcemulon the young have the snout proportionally much shorter, 

 so that the maxillary, although also shorter in proportion, extends fur- 

 ther back in comparison with the eye. Nearly all the species have, 

 when young, two more or less sharply-defined, dark, longitudinal stripes 

 along the side, one or more along the top of the head, and a dark spot 

 at the base of caudal. These markings persist Iftnger in some species 

 than in others, but traces of them, at least, may be found in the young 

 of nearly all the species of Hcemulon and Pomadasys. In a few species 

 these markings persist during life. 



The species are all essentially alike in respect to the pores at the chin, 

 the height and form of the soft dorsal, the form of the nostrils, the squa- 

 mation of the fins, the direction of the lateral line, &c. These common 

 characters are, therefore, not mentioned in the following descriptions. 

 The ijeritoneum is black in all species examined: 



Synonymy of the genus H^mulon. 



DiABASis, Desmarest t Premifere D6cade Ichthyologique, 1823, 34 {parrce ; flavolineatus ; 



not of Hoffmannsegg, Coleoptera, 1819; also used in botany). 

 HiEMULON, Cuvier, ll&gne Animal, ed. 2, 1829 (eZegraws, etc.). 

 Orthostcechus, Gill, Proc. Ac. Nat. Sci. Pliila., 1862, 255 (macuUcauda). 

 H^MYLUM, (Scudder MSS.) Putnam, Bull. Mus. Comp. Zo61.,1863, 12 {elegans, etc.). 



•Bleeker, Systema Percarum Revisum, adopts the name Diabaais, assigning the date 

 " 1818 ?" The date given on the title page of Desmarest's paper is 1823. It is stated 

 by Desmarest that the paper was read before the Linnsean Society of Paris, December 

 16, 1822. 



t Le poisson que je viens de d^crire me paralt, selon les principes de classification 

 ichthyologique de M. Cuvier, devoir former un genre ^ part. Je lui donne le nom de 

 DiahaHia Aiai3a<TLc (transitio) pour iudiquer sea rapports, d'une part, avec les Acanthop- 

 terygiena des genres Lutjan et Pristipome, et del'autre avec les poissons placds dans la 

 famille des Squamipenues. 



