116 PROCEEDINGS OF THE ACADEMY OF 



anal fin, which is deeper than long, is inserted opposite the posterior portion 

 of the base of the dorsal. The ventrals are small, subtriangular when expanded, 

 their posterior extremity not extending as far as the anterior edge of the anal. 

 The pectorals are well developed, elongated, posteriorly rounded off, their ex- 

 tremities projecting beyond a line drawn at the origin of the ventrals. The 

 rays of the fins are : D 12 ; A 10 ; C 7, 1, 8, 7, 1, 6 ; V 6 ; P 9. We have 

 counted thirteen rays in the dorsal fin of the male sex, and seven in the anal. 

 The structure of the latter is as follows : First and second ray simple, short, 

 and slender; third and fourth most developed, third one stoutest; fifth, sixth, 

 and seventh slender, but deeper than the first and second, and bifurcated. The 

 scales are very similar in either sex, much deeper than long, anteriorly trun- 

 cated, with numerous radiating furrows upon the latter section only, and 

 rounded off upon the remaining edges, with very fine concentric lines of growth. 

 The ground color is olivaceous brown ; the dorsal region assuming a darker 

 tint, owing to a biowu spot which may be observed on the scales, whilst the 

 abdominal region has a lighter and more yellowish aspect. The dorsal fin 

 alone exhibiting transverse series of blackish spots : the other fins being 

 unicolor. 



XLVI. Lieut. D. N. Couch has collected, in the waters of the Rio San Juan, at 

 Cadarecta and Monterey, in the Province of New Leon, a species of Limia, which 

 differs widely from its congeners, as will be shown presently. Unfortunately, 

 all the specimens are of the female sex. The largest of these measure one and 

 five-eighths of an inch, being apparently full grown, or, at any rate, adult, for 

 the abdomen is distended by the presence of numerous embryos. The body 

 appears to be rather short and contracted ; the back being convex and gently 

 sloping forwards. The head is small, constituting about the fifth of the total 

 length. The orbit occupies the third of the side of the head. The dorsal fin 

 is longer than high, superiorly subconvex, its anterior margin being nearer the 

 insertion of the caudal than the apex of the snout. Its entire base is placed 

 upon the posterior declivity of the back. The posterior margin of the caudal 

 is. as usual, convex. The anal fin is inserted opposite the posterior portion of 

 the base of the dorsal ; it is narrow and rather deep, and its extremity extends 

 further back than theposterior rays of the dorsal. The ventrals are compara- 

 tively of moderate size, sublanceolate, their extremity extending to the vent. 

 As to the pectorals, they are narrow and elongated, rounded off posteriorly, 

 not reaching a vertical line drawn nt the insertion of the ventrals. The rays 

 are : D 9 ; A 6 ; 4,1,9,8,1,3; V 6 ; P 11. The scales are very large, and 

 exhibit the general structure alluded to in the other species. The dorsal re- 

 gion to the middle of the flanks is almost entirely chestnut-brown, so large are 

 the spots which are observed on every scale. An obsolete band of black exists 

 along the sides. The abdomen and inferior region of the tail are yellowish, 

 with a golden reflect. The fins are unicolor, except the dorsal, which exhibits 

 a few blackish spots. We call this species Limia couchiana. 



XLVII. Another species of Limia appears to be common about Matamoras, 

 where it was first collected by the late L. Berlandier, whose collection has 

 since been purchased by Lieut. D. N. Couch, a lover and. cultivator of natural 

 sciences. 



Specimens of the male sex measure nearly two inches in total length, of 

 which the head, which is rather small, constitutes about the fifth part. The 

 body is very much compressed, rather deep, maintaining its depth along the 

 peduncle of the tail. The upper surface of the head, as usual, is very much 

 depressed and flattened. The profile is gently sloping from the origin of the 

 dorsal fin to the apex of the snout. The eye is well developed, subcircular, its 

 diameter entering about three times in the length of the side of the head. The 

 dorsal fin is longer than high, and equally elevated throughout its whole length, 

 the tip of its posterior rays not extending as far as the insertion of the caudal 

 fin. The anal is inserted somewhat posteriorly to the anterior margin of the 



[April, 



