ACANTHOPTEliYGIANS. 95 



Hklotes, CtlV. 



Also very similar; have the dorsal fin deeply emarginate, and are particu- 

 lurly distinguished by their anterior range of teeth being trilobate*. 



Most of these fishes have longitudinal blackish lines on a silvery 

 ground. 



The Perches with less than six branchial rays and two dorsals consti- 

 tute but two genera. 



Triciiodon, Steller. 



The preoperculum of which has very strong spines, and the operculum 

 of which terminates in a flat point; they have no scales; their mouth is 

 cleft almost vertically. But one species is known, 



Tr. Stelleri, Cuv. ; Trachinus trichodon ; Pall. Mem. de Petersb. 

 IV, XV, 8, and Cuv. and Val. Ill, Ivii. From the north of the 

 Pacific j". 



SiLLAGO, CllV. 



Head somewhat elongated and pointed; mouth small; teeth dense, as 

 the pile on velvet, in the jaws and before the vomer; an operculum termi- 

 nating in a small spine; six branchial rays; two contiguous dorsals; 

 spines of the first slender, the second long and low. 



They are all from the Indian Ocean, and much esteemed for the 

 flavour and delicacy of their flesh. The most remarkable species is 

 Sill, domina, Cuv. ; Le Peche Madame de Pondicherry. Brown- 

 ish, and distinguished by the first ray of its dorsal, elongated into a 

 filament as long as the body. Its head is scaly, and the eye very 

 small. There is another. 



Sill, malaharica; Scicetia malaharica, Bl. Schu. ; Soring, Russel, 

 113; Le Peche bicQut; not above a foot long, and fawn-coloured, 

 which is considered one of the best fishes of India J. 



We now pass to those Perches which have more than seven rays to the 

 branchiae. Three genera are known, all of which present the following 

 peculiarity, that their ventral fins have a spine and seven or more soft 

 rays, while in other Acanthopterygians there are never more than five 

 soft rays. 



HoLOCENTRUM§, Arledi. 



The Holocentri are beautiful fishes with brilliant and dentated scales, 



* Heloiis 6-lincatus, Cuv. et Val. Ill, Ivii, or Esclave six lignes, Quoy et Gaym., 

 Voy. de Freyciii. Zool. LXX, ]. 



t This fish having neither jugular ventrals, nor an elongated posterior dorsal, nor 

 a strong spine on the operculum, nor seven rays in the branchiae, cannot be a Trachi- 

 nus, as was thought by Pallas and Tilesius. 



+; Add, Atherima siliama, Forsk., or Plutlcephalus sihavms, Bl. Schn. Ruppel, 

 Poiss. pi. iii, f. 1 ; Sillago maculata, Quoy et Gaym. Freyciii. pi. iii, f. 3. 



§ We restrict this genus to species answering to the definition of it given by Ar- 

 tec;!, h'cb III, ad tab. xxvii, 1, ar.d, like him, we give a neuter termination to this 



