14 ZOOLOGY OF THE VOYAGE OF THE BEAGLE 



warrant such a step. Its herring-like form, denticulated suborbital, scaly maxil- 

 lary, small pectorals, backward position of the ventrals, and deeply forked caudal, 

 sufficiently distinguish it from Centropristes, with which it hardly agrees in any 

 of its characters, beyond that of wanting canines, and having the preopercle denti- 

 culated, and the opercle armed with small sharp points. Its teeth, however, are 

 not exactly velutine, as in the typical species of that genus, but rather in fine card, 

 with the outer row in both jaws stronger than the others. But, perhaps, one of 

 the most marked peculiarities in this proposed genus resides in the scales, which 

 have, instead of the usual fan of diverging striae on their basal portions, a triangu- 

 lar space filled up by a number of extremely fine, closely-approximating striae, 

 parallel to each other, and also parallel to the basal margin, which is cut quite 

 square and entire.* 



Although this genus is thus separated from Centropristes, there is no doubt 

 of its having a near affinity with it ; and also with Grystes, from which last, how- 

 ever, it is at once known by its denticulated preopercle. It is still more closely 

 allied to Apsilus, which it very much resembles in its general form, as well as in 

 some of its particular characters. Amongst other points of resemblance with this 

 last genus, may be noticed the similarity of the teeth ; the very large gill- 

 opening ; the small and inconspicuous points on the opercle ; the weak spines of 

 the dorsal and anal, both which fins also terminate in a point behind; the small 

 pectorals, and the deeply forked caudal. 



It is probable that the Centropristes truttaceus of Cuvier and Valenciennes 

 also belongs to this new genus, which, as well as the C. Georgianus, comes from 

 New Holland, and which those authors seem, not without much hesitation, to 

 have placed provisionally in the group in which it now stands. It is not stated, 

 however, whether the peculiar character of the scales in the C. Georgianus, above 

 pointed out, exists also in this species. 



Arripis Georgianus. 



Centropristes Georgianus, Cuv. et Val. Hist, des Poiss. torn. vii. p. 338. 



Form. — As M. Valenciennes has given an accurate and detailed description of this fish; and as I 

 have already stated above some of its leading characters, it is not necessary to say much 

 further on this head in reference to the specimen in Mr. Darwin's collection. I need only 

 point out wherein it differs from the description in the " Histoire des Poissons," the greater 

 part of which applies exactly. M. Valenciennes states that the ventral profile is more curved 

 than the dorsal, but there is not much difference in their respective degrees of curvature in this 



* The absence of the usual fan has suggested the name of Arrijns, from a priv. et pnns, flabellum. 



