ICHTHYOLOGY. 



57 



rather deep and very much compressed ; the caudal fin deeply furcated. The eye is circular, 

 and its diameter contained four times in the length of the side of the head. 

 The rays of the fins are : 



D 2, 8 ; A 2, 8 ; C 6, 1, 9, 8, 1, 6 ; V 8 ; P 13. 



The color is of a reddish brown tint above ; silvery white beneath. The middle of the flanks 

 exhibits an indistinct or rather diffused silvery, sometimes blackish band. 



Syn.— Moniana frigida, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 200. 



Plate XXX, fig. 17, represents Moniana frigida, size of life ; fig. 18, a dorsal scale ; fig. 19, 

 a scale from the lateral line ; fig. 20, a scale from the abdominal region. 



List of specimens. 



Catal. Corres. No. 



No. 



100 



123 



98 



124 



of teeth. 



2G96 



2707 



No. of Age. 



spec 



3 



100 

 10 



Locality. 



Adult. 



do 



..do.. 





Rio Salado, Texas 



do 



Rio Sabinal, Texas 



20 ..do.. I Rio Medina, Texas 







When col- 

 lected. 



Whence obtained. 



1851 

 1851 

 1851 

 1851 



Nature of 

 specimen. 



Col. J. D. Graham Alcoholic. 



do 



do 





do 



Collected by 



do 



do 



do 



John H. Clark. 



do 



do 



do 



4. MONIANA COUCHI, G r d 











Plate XXX, Figs. 21—24. 



Resembles Jf. gracilis most ; is, however, distinguished from it by a less fusiform body and a 

 much shorter head. This feature may be traced upon series of specimens of both species with 

 an unfailing constancy. The eye is also smaller, and so is the mouth, as might be deduced 

 from the traits just alluded to. 



Syn. — Moniana couchi, Grd. in Proc. Acad. Nat. Sc. Philad., VIII, 1856, 201. 



Plate XXX, fig. 21, represents Moniana couchi, size of life ; fig. 22, a dorsal scale ; fig. 23, 

 a scale from the lateral line ; fig. 24, a scale from the abdominal region. 



List of specimens. 



i 



Catal. Cor. No. 



No. 



103 



of teeth. 



2699 



No. of 

 spec. 



20 



Age 



Locality 



When col- 

 lected. 



Adult. China, New Leon, Mexico. 



J 853 





Whence obtained. 



Nature of 

 specimen. 



Collected by 



Lt. D. N. Couch.. Alcoholic. 



Lt. D. N. Couch... 





5. MONIANA EUTILA, Grd. 

 Plate XXX, Figs. 1—4. 



Has the general physiognomy of M. gracilis, from which it differs by a more advanced position 

 of the dorsal fin, and by larger scales. Dorsal region greyish ; sides and abdomen golden. 



Syn.— Moniana rutila, Grd. in Proc. Acad. Nat. Sc. Philad. VITI, 1856, 201. 



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