102 ACANTHOPTERYGII. 



Family, II— SQUAMIPINNES, Cuv. 



Chcetodontidce, pt. Richardson. 



Branchiostegals six or seven (Zanclus four) : pseudobranchise well developed. Body elevated and 

 compressed. Eyes lateral and of moderate size. Mouth generally small, with a lateral cleft, and situated in 

 front of snout. Teeth villiform or setiform, neither incisors nor canines : in most of the genera the palate is 

 edentulous, soft portion of the dorsal fin of greater extent than the spinous, sometimes considerably more, 

 rarely slightly so : anal with three or four spines, its soft portion similar to that of the dorsal : lower pectoral 

 rays branched : ventrals thoracic, with one spine and five rays. Scales cycloid, or very finely ctenoid, 

 extending to a greater or less extent over the vertical fins, but occasionally absent from the spinous portion. 

 Air-vessel present, generally simple. Intestines usually much convoluted ; stomach cascal. Pyloric appen- 

 dages in moderate numbers. 



Geographical distribution. — These fishes are, as a rule, marine, and although some have been recorded as 

 taken in rivers and estuaries, they are rarely captured above tidal reach. 



The Squamipinnes have been divided by Dr. Giinther into three groups : — First, those which have the 

 palate edentulous (Ghcetodontina) : secondly, those which have teeth on the palate, but the dorsal fin is situated 

 in the posterior half of the length of the back (Toxotina) : and thirdly, some Australian forms wherein there 

 are palatine teeth, and the dorsal fin occupies the middle of the length of the back, (Scorpidina) . 



In some species a prolongation of the dorsal fin, owing to sex, may be present as in Holacanthus imperator, 

 H. annularis, &c. 



SYNOPSIS OF GENERA. 



First group — Chsetodontina. 

 No palatine or vomerine teeth : no concealed spine in front of the base of the dorsal fin in the adult. 



1. Chcetodon. Snout of moderate length or short : no preopercular spine : a single un-notched dorsal 

 fin without an elongated spine : anal with 3 or 4 spines. 



2. Clielmo. Snout much produced : no preopercular spine : 9 to 13 dorsal spines none of which are 

 elongated. 



3. Heniochus. Snout of moderate length : no preopercular spine : 11 to 13 dorsal spines, the fourth being 

 much elongated. 



4. Zanclus. Snout of moderate length : no preopercular spine : 7 dorsal spines, the third being much 

 elongated. 



5. Holacanthus. Snout of moderate length : a strong preopercular spine : 11 to 15 dorsal spines, none 

 of which are elongate. 



6. Scatopharjus. Snout of moderate length : no preopercular spine : dorsal fin notched and no scales on 

 the spinous portion : anal with 4 spines. 



7. Ephippus. Snout short : no preopercular spine ; dorsal fin deeply notched, with 8 or 9 spines several 

 of which are elongated and flexible. 



8. Drepane. Snout short : no preopercular spine : dorsal fin deeply notched, with 8 or 9 spines, none of 

 which are elongated. 



Second group — Toxotina. 



Vomerine and palatine teeth : no concealed spine in front of the base of the dorsal fin which is 

 situated in the last half of the back. 



9. Toxotes. Snout somewhat produced. Dorsal fin with 4 or 5 spines. 



The young fishes in some of the above genera of the first group show considerable enlargement of the 

 bones of the head which more or less disappear in the adult,* in a few a concealed spine pointing forwards may 

 be present in the immature in front of the base of the dorsal fin. 



* Genus — Tholichthts, Giinther. 

 Dr. Giinther (Annals and Mag. of Nat. History, 1868, p. 457) described and figured a very small fish, 11 millims. long, as a 

 new Cyttoid Genus, which he termed TholicMhys. I obtained several (I think thirteen) larger ones at Madras lyV inches long, which I 

 described (Proc. Zool. Soc. 1870, p. 687,) as T. osseus, but drew attention to their belonging to the Family Squamipinnes, giving it a 

 strong resemblance to Heniochus or Ch&todon. I personally deposited my largest specimen in the British Museum, but as it has been 

 mislaid I have figured my next largest at twice the natural size ; it is unfortunately dried, all my specimens in spirit, irrespective of the 

 one previously mentioned, having become spoiled during their transit from India. 



