62 ZOOLOGY OF THE VOYAGE OF THE BEAGLE. 
Mr. Darwin’s collection contains two individuals of this species procured on 
coral reefs at the Keeling Islands. As according to his notes made from the 
recent fish, the posterior half of the body is bright orange, Bloch’s figure may not 
be so much overcoloured as is supposed by Cuvier and Valenciennes, who state 
that he has represented of a bright red, what ought to be silvery grey and yellow 
ochre. Perhaps the colours may depend in some measure on the season. Mr. 
Darwin’s specimens were obtained in the month of April. 
Genus—STEGASTES.* Jen. 
Corpus oblongo-ovale, compressum. Caput obtusum. Os parvum, haud protractile. 
Dentes maxillares omnes incisores, parvi, equales, contigui, unisertati ; palatine 
velutini, minuti. Ossa suborbitalia denticulata. Preoperculum margine adscen- 
denti levissimée denticulato. Operculum inerme. Membrana branchialis quatuor- 
radiata. Pinne verticales squamis confertis fere omnino obtecte: dorsalis unica, 
subequalis, membrand ad apices spinarum parum laciniatd: ventrales radio primo 
molli elongato. Linea lateralis sub terminationem dorsalis interrupta. Squame 
rostri et verticis parve ; operculi et corporis magne, oblique disposite ; omnes 
levissime ciliata. 
This apparently new form will enter into none of the genera established by 
Cuvier and Valenciennes. The palatine teeth serve to detach it from the Scienide, 
while this character, taken in connexion with the compressed body, and the 
extreme scaliness of the vertical fins, require that it should be arranged with the 
Chetodontide, or at least have a place in that large group to which Cuvier has 
given the name of Squammipennes. It belongs to the second tribe in that family 
characterized by cutting teeth; and it would seem most nearly allied to Pime- 
lepterus, but it does not approach that genus very closely, and may at once be 
distinguished from it, by the teeth being without spurs behind, and the dorsal and 
anal fins being more scaly. From Dipterodon, the only other genus in that tribe, 
it may be known by its undivided dorsal, independently of other marked dif- 
ferences. 
But though this genus requires to be arranged with the Chetodontide on the 
grounds above mentioned, in all its other characters it comes much nearer that 
portion of the Scienide which have the lateral line terminating beneath the end 
of the dorsal fin; especially Pomacentrus, which it resembles in the general form 
* Yreyaorns, tector. 
