21 



with numerous black points in the male, es- 

 pecially during- the spawning season. 



L. gibbosa, like the other fishes of this fam- 

 ily, is not held in great estimation as an arti- 

 cle of food. It is taken in some numbers in 

 the lower waters of the Sacramento and San 

 Joaquin in nets. It is sold by the fishermen 

 here, under the name of Chub, and is also 

 very absurdly called by some of them Pike. 

 Indeed this family of Cyprinidae seems to 

 be a favorite one with them for exercising 

 their ingenuity in the misapplication of 

 names. Gila grandis, as stated (Pr. Cal. Ac. 

 Nat. Sc. vol. 1. page 19,) they call Salmon 

 Trout, and Lavinia cornpressa, following the 

 same principles of nomenclature they name 

 Herring. 



Lavinia cornpressa, Ayres. — This species is 

 brought to our markets in company with the 

 preceding, which it about equals in size. — 

 My description is taken from a specimen 

 eleven and a half inches in length. 



Form elongated, compressed ; the greatest 

 depth contained in the length not including 

 the caudal fin, three and a half times ; dppth 

 at the caudal fin, a little more than one-third 

 of the greatest depth; thickness in front of 

 the dorsal fin a little more than one-half of 

 the depth at the same point. 



Head rather small, with the upper and 

 lower outlines taperiug to a somewhat acute 

 snout, but without any depression separating 

 the head from the body, and with the dorsal 

 surface of the head not concave. Length of 

 the head contained in the total length not in- 

 cluding the caudal fin, four and a half times. 

 Mouth small, the tip of the maxillary not by 

 any means reaching the plane of the orbit. 

 Lower jaw shorter than the upper. No bar- 

 bels. Eye nearly circular, its diameter not 

 contained quite five times in the length of 

 the head. 



Posterior aperture of the nostrils the larger, 

 with a slight valvular projection on its ante- 

 rior border. 



The lateral line curves gently downward, 

 neaily as far as the ventrals, then ascends, 

 and does not assume a straight course till it 

 has neatly pa ised the anal fin. 



fhe dorsal fin arises further back than in 

 L. gibbosa, being nearly equidistant bet 



and the tip of the central caudal 



rays. The height or the fin, which ex< ,ls 



us length l>y not quite one fifth, is a little less 

 than ■ th ol the total length. 



The anal fin arises about on a plane with 



the termination of the dorsal; its height and 

 length are both a little less than those of tha 

 fin. 



The ventrals arise a very little in advance 

 of the dorsal; their height equals the length 

 of that fin. 



The pectorals are rounded, equalling the 

 ventrals. 



Caudal fin concave; the height of the outer 

 rays equalling the length of the head. 



D. 4-10; A. 3-11; V. 1-9; P. 16; C. 19 with 

 nine accessories. 



Scales not quite so large as in L, gibbosa, 

 being about sixty two along the lateral line, 

 and twelve in an oblique line above it at the 

 origin of the dorsal. 



Color very light greenish brown on the 

 back, silvery on the sides and beneath; sides 

 of the head tinged with flesh color. 



L. cornpressa appears to be less common 

 than L. gibbosa. Both species aresomewha 

 closely allied to L. crasskauda B. and G. and 

 to L. conformis B. and G. They differ how- 

 ever from them both, in the size and form of 

 the head, the proportions of the body, the 

 size of the eyes, the fins and the scales. 



Dr. W. P. Gibbons presented a communi- 

 cation from Dr. B. Dowler of New Orleans 

 on viviparous fishes discovered in Louisiana. 



The following works were received from 

 Dr. Gwin — Report on the Exploration of the 

 Valley of the Amazon by Lieut. Gibbon, 

 Eighth Report of the Smithsonian Institu- 

 tion, Cruise of the Dolphin, and Report of 

 the U. S. Coast Survey for 1852. The thanks 

 of the Academy were voted for the donation. 



Dec. 25, 1854. 



Dr. J. B. Trask in the chair. 

 Dr Wm. 0. Ayres presented the following 

 description of a new Cyprinoid fish. 



Gila microlepidota, Ayres. — This species 

 which is brought, not unfrequently, to our 

 markets, appears seldom to exceed twelve 

 inches in length. It is sold by many of the 

 fishermen under the name of Fan-tad, from 

 the peculiar form of the caudal fin; like the 

 others of the Cyprinidae, it is not^much es- 

 teemed. 



Form elongated, subcompressed, rather 

 slender, tapering must posteriorly. Greatest 



depth contained about live and a half times 



in the total length; length of tin- head, about 



lour and a hall limes in the same; depth an- 

 terior io the caudal not quite one third of the 

 greatest depth. Head tapering regularly from 



