502 PROCEEDINGS OF THE ACADEMY OF 



By its cavernous skull, it suggests the Sciaenoids and the Acerince among 

 the Percoids, but from both, it is at once separated by the long anal fin which 

 is nearly equal to the dorsal, and by other morphological and anatomical 

 characters, which the description of the family given above will at once sug- 

 gest. 



Among the Percoids, it most resembles the species usually known under the 

 name of Acerina schraitzer,* but as will be readily learned on comparison, the 

 resemblance is simply analogical. 



Among the Scisenoids, the most analogous forms appear to be the genera 

 Pachypops of Gill, and Pachyurus of Agassiz, or Lepipterus of Cuvier. The 

 squamation of the fins, characteristic of the Sciasnoids, in addition to the short- 

 ness of the anal fin of those genera, and the peculiarly dense squamation of 

 the caudal fin of Pachyurus, evidently show that they are true Sciaenoids and 

 exclude the entertainment of any strict or close affinity to the Sillaginoids. 



From the Trachinoids and the allied forms with which the family has been 

 associated by Dr. Gunther, it is at once separated by the form and structure 

 of the head. 



Originally referred by Cuvier to the family of Gobioides, it was subsequently 

 transferred to the division of the Percoides with thoracic ventrals, less than 

 seven branchiostegal rays, and provided with two dorsal fins. The only other 

 genus referred to that section was Trichodon. 



Sir John Richardson, in his Report on the Fishes of the Chinese and Japan- 

 ese waters, framed for it a new family, but subsequently placed it in his family 

 of Uranoscopidae. 



Dr. Bleeker also, at one time, appears to have regarded the family as valid, 

 and named it Sillagoidei. In his recent classification, he has removed it to 

 the family of Sciaenoids, and thus arranged it : 



Familia 84. SCOENOIDEI SCLENINI Bp. 



Subfamilia 1. ACERIN^FORMES. 

 Gen. Acerina Cuv., Coptodon Gervais. 

 Subfamilia 2. SILLAGINIFORMES. 

 Gen. Sillago Cuv., Sillaginichthys Blkr., Aspeo Cuv. 

 Subfamilia 3. SCI.ENIFORMES. 

 Gen. All Sciaenoids of Gunther, except Conodon and Eleginus, the former of 

 which is a Pristipomatoid and the latter a Notothenioid. 

 The characters which distinguish the Sillaginoidae from the Sciaenoidae have 

 been previously enumerated. The differences existing between them and 

 Aspro are still more decided. As previously remarked, the resemblance to 

 Acerina is much greater. The genus Coptodon is not at all related to Acerina, 

 but is a synonyme of Tilapia, the type of which is closely allied, if not identi- 

 cal with the Chromis niloticus of Cuvier.f 



SILLAGO, Cuv. 



Synonymy. 

 Sillago Cuv., Regne Animal, ed. i., vol. ii., p. 258, 1817. 



" Cuv. et Vol., Histoire Naturelle des Poissons, vol. iii., p. 398. 



*The Acerina schraitzer appears to be the type of a distinct genus, to which the name 

 of Leptoperca may be given. The genus diners from the restricted Acerina by the more 

 slender body and head, and longer dorsal and anal fins. 



f The name of Chromis cannot be retained for the C. niloticus, as the type of that 

 genus is the Sparuschromis of Linne\ (see Mem. du Museum d'Hist. Nat., tome i, p. 353, 

 355.) The name of Tilapia, though proposed by Sir Andrew Smith, under an erro- 

 neous view of its affinities, may be then accepted. The reference by Gervais of a species 

 of the genus to Aceiina, as was originally the case, is, to use the mildest expression, sin- 

 gular. 



[Dec. 



