FISH. 



79 



to each other, and also to the space just alluded to. From the end of the second dorsal to the 

 commencement of the caudal is exactly one-sixth of the entire length. The posterior half of 

 the anal nearly answers to the second dorsal, but the two fins do not terminate exactly in the 

 same line, the dorsal extending a little the furthest. Caudal forked for about half its length. 

 Pectorals about two-thirds the length of the head. Ventrals attached at a point beyond the 

 extremity of the pectorals. Breadth of the silver band about one-fifth the depth of the body. 

 Colour. — Not noticed in the recent state. In spirits, the back and sides above the silver band 

 are brownish, with the contour of each scale marked out by black dots. All below the band 

 appears to have been silvery. The band itself is not very brilliant. Both the dorsals, as well as 

 the caudal, are dusky : anal and ventrals pale. 



A second specimen does not differ from the above, excepting slightly in the fin-ray for- 

 mula, which is as follows : 



D. 5 — 1/10; A. 1/15; &c. 

 Habitat, Valparaiso. 



This species was found by Mr. Darwin at Valparaiso in fresh water, in the 

 month of August. It would seem to be nearly allied to the A. laticlavia of Cuvier 

 and Valenciennes, brought from the same locality by M. D'Orbigny ; but, judging 

 from the short description in the "Histoire des Poissons," it is more elongated, and 

 has the head longer in relation to the depth of the body ; also has the silver band 

 narrower. In the A. laticlavia, the head is said to be equal to the depth, and to 

 be contained six times in the entire length ; the breadth of the silver band to be 

 greater than in any other species. In the A. microlepidota, the depth is 

 one-eighth and the head one-sixth of the length : the silver band not broader than 

 in the A. argentinensis and some others. The colouring also of the fins appears 

 different in the two species. 



3. Atherina incisa. Jen. 



Plate XVI. Fig. 2. Nat. size. 



Fig. 2. b. Twice nat. size. 

 Fig. 2. a. Magnified scale. 



A. gracillima; corporis altitudine partem vix nonam, capite sextant, longitudinis 

 cequante : oculis mediocribus : maxillis cequalibus, valde prolractilibus ; commissurd 

 primum horizontal*, posterius deflexd : dentibus velutinis, in maxilla inferior e 

 minutissimis : dorsali prima omnino pone ventrales reclinatas locata : squamis 

 mediocribus, seriebus longitudinalibus duodecim ad maximum dispositis, marginibus 

 liberis inciso-crenatis : vittd laterali nitide argented. 



D. 5—1/8 ; A. 1/17 ; C. 17 ; P. 12 ; V. 1/5. 



D. 5—1/9; A. 1/19; &c— 



D. 6—1/10; A. 1/19; &c— 



Long. unc. 2. lin. 6. 



