484 rROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



OIV THE FAlTIir.V C^EIVTKOPOitHO/E. 



BY TIIEOI>ORE GILL. 



The genus Centropoinus of the uropical American seas aud rivers has 

 generally been referred to the family Percidii'. As long ago as 1865, 

 however, I was struck by the remarkable differences in its osteology from 

 any other fishes known to me, and communicated the results of my 

 examination to Professor Poey, who agreed with me that the type was 

 entitled to family distinction. Both Pri)fessor Poey and myself have, 

 therefore, isolated the form in question as a peculiar family. That 

 family has, however, n^t yet been characterized, and the object of this 

 communication is to indicate some of the most peculiar features which 

 distinguish the form from those with which it has been usually associ- 

 ated. The want of an accessible large collection of skeletons precludes 

 a detailed comparison with many types, but most of the American genera 

 of Percid;^, (typical), Labracid*, Serranidaj, and Sparida? have been 

 examined as to their skulls at least. It is possible that the genus Lates 

 aud even Ni])hon may be more nearly related, but no skeletons of those 

 fishes are available. It is to be hoped that the present notice may at- 

 tract attention to their relations. 



CENTROPOMID^. . 



Synonijmn as families. 



= Centiopomida.', Gill, MSS., 1865. 



= Cciitropomatidi, Foei/, Eepertorio Fisico-Natural de Cuba, v. 2, p. 280, 1868 (not 



definect). 

 = Centropomida^, Gill, Arrangement Families of Fishes, p. 11, 1872. 

 Percoides and Percidicgen., autliors generally. 



As will be seen, Professor Poey was the first ichthyologist to publish 

 a name for the family. 



Typical Acanthopterygians with the postorbital portion of the skull 

 longer than the oculo-rostral ; the i)arietals behind the constriction 

 continuous with, the epiotics and transverse lamina? arising from the 

 suproccipital cre^t, the three together forming a well difi'erentiated 

 posterior oblong pentagonal or hastiform area; the re-entering parie- 

 tal sinus, with its anterior margin, produced fowards nearest the opis- 

 thoiics ; the exoccipitals well developed and contiguous above the fora- 

 men magnum ; the vertebra^ in typical number (10 + 14) and longish ; 

 the anterior two partly co-ossified and the first with selliform apophyses 

 extending backwards and embracing the second vertebra ; the vertebrae 

 mostly with fovea? or pits for the ribs aud only with developed para- 

 pophyses for the posterior (0-10) pairs of ribs ; the second neural spines 

 suberect, and with laminiform extensions which embrace the first ; the 

 neurapophyses and neural spines of the other vertebra' depressed at 

 their bases, continuous with the zygapophyses in front, and slightly 

 curved upwards at their tips ; the htemal spines resembling the neural. 



