20 ON THE ICHTHYOLOGICAL SYSTEM 



in part to the chaetodonoids by the sensible character of the 

 scales which spread over some parts of their vertical fins, and 

 in part they assimilate with the sparoids by the total absence 

 of their scales. 



Gradations no less delicate connect certain genera of the 

 spari, such as the smaris and gerres, with others like the 

 equulae, which cannot be remote from the zeus ; and these lead 

 in their turn to the scombri, who finally pass by gradations 

 so sensible into riband shaped fishes or taenioides, as to 

 make the point of sepai*ation undeterminable. Naturalists, 

 therefore, who were solicitous to place animated beings 

 according to their relative characters, had no choice but to 

 group the acanthopterygian fishes, known in other systems 

 by the generic names of perca, sciaena, sparus, chaetodon, 

 zeus, scomber, cepola, &c. into one vast family, notwith- 

 standing the immense number of species it includes. It is 

 true certain shades, indicating subordinate groups, are per- 

 ceptible, but no species is so circumscribed by distinct pecu- 

 liarities, as to suffer complete separation. 



There is not quite so intimate a connection among the 

 Lophii, Batrachi, Gobii, Blennii, and Labri, their characters 

 are in general sufficiently clear, and though in part anato- 

 mical, they are readily discovered ; the small opening at the 

 gills of the first of these groups, with pectoral fins prolonged 

 in the form of arms; similar pectorals joined to three rays of 

 the ventrals in the second ; the flexible spines on the backs 

 of the third and fourth ; the fleshy lips of the fifth ; and, 

 finally, the total absence of cascal appendages in them all, 

 are sufficient to divide them from all other acanthoptery- 

 gians ; and this last-mentioned character begins to approx- 

 imate them towards siluri and cyprini, whose families are at 

 the head of the malacopterygian, and in their turn link them- 

 selves with acanthopterygians by the spines of some of the fins. 



