FISH. 73 



mences opposite the fourteenth ray of the second dorsal, and is similar in form to that fin, but 

 of course shorter, and also less elevated at its anterior extremity : finlet and the intervening 

 space exactly corresponding. Caudal deeply forked ; the lobes very long and pointed, each 

 equalling nearly one-fourth of the entire length ; the middle rays not one-fourth the length of 

 the lateral ones. Pectorals attached a little below the middle ; in length a little exceeding half 

 that of the head. Ventrals about the same size as the pectorals, but attached a little 

 further back. A slight elevation at the sides of the tail, but no distinct keel, properly so 

 called. 



D. 6—1/24—1 ; A. 1/16—1 ; C. 17, &c. ; P. 20; V. 1/5. 

 Length 18 inc. 3 lines. 

 Colour. — " Band on the side azure blue ; above a duller greenish blue ; beneath two greenish 

 metallic stripes: lower half of the body snow white."— D. No trace of the longitudinal 

 stripes remains in the dried skin. 

 Habitat, Keeling Island, Indian Ocean. 



A tolerably exact figure of this species occurs in the Zoological Atlas of 

 Freycinet's Voyage, but I can find no notice of it in the " Histoire des Poissons " 

 of Cuvier and Valenciennes. Although referred by Cuvier in his " Regne Animal " 

 to Seriola, it rather departs from that genus in some of its characters. Inde- 

 pendently of the spurious unlets in the dorsal and anal fins, which separate it 

 from all the other species, I see no trace of any reclined spine before the first 

 dorsal, nor of two free spines before the anal ; in both which respects Seriola is 

 said to resemble Lichia. Possibly, however, as Mr. Darwin's specimen is a dried 

 skin, these characters may have been destroyed in the process of preparation. 

 And to the same cause, perhaps, is to be attributed the circumstance of my not 

 being able to observe more than one spine in the true anal, Quoy and Gaimard 

 mentioning two. On the other hand, these naturalists appear to have overlooked 

 the narrow pointed scales on the upper part of the cheeks, which are of a different 

 character from the scales on the body. 



Mr. Darwin's specimen of this species was obtained at the Keeling Islands. 

 The one figured in Freycinet's Voyage was procured at Papua or New Guinea. 

 It probably, therefore, has a considerable range over the Indian Ocean. 



PSENES 1 



Psenes leucurus, Cuv. et Vol. ? Hist, des Poiss. torn. ix. p. 197. 



Mr. Darwin's collection contains two individuals of a species of Psenes, in 

 reference to which his notes state that they were taken in Lat. 17° 12' S., 

 Long. 36° 33' W., a hundred and twenty miles from the nearest land above water, 

 though shoals were considerably nearer. They do not measure more than one 

 inch eight lines in length ; and from their small size, and their not being in a very 



