1856.] 171 



line possessed by almost all fishes. The body is elongated and compressed ; 

 the head small ; the mouth small also, opening obliquely forwards and down- 

 wards. The lips being small and trausversally ridged ; the inferior one being 

 slightly bilobed. The anterior margin of the dorsal is situated in advance of 

 the insertion of the ventrals. The dorsal fin itself is either higher than long, or 

 else its length is equal to its height, varying somewhat according to the sexes, 

 as well as the anal, which is, however, always deeper than long. The shaft of 

 the pharyngeal bones constitutes a very open curve, the convex margin of 

 which is regular and entire. The teeth themselves are very much com- 

 pressed, strongly curved inwardly, and much larger inferiorly than supe- 

 riorly. 



To this genus we add four new and very distinct species, inhabiting the 

 South Western waters. 



1. MoxosTOMA CLAViFORMis. This species has been known to us for several 

 years. Its general outline has a club-shaped appearance, a trait though more or 

 lessgenerical, is especially characteristic here. The largest specimens which we 

 have examined are four inches in total length, and in all probability not very 

 young. Thegreatestdepth,ta]ien across the pectoral region, is containedfour times 

 and a half in the total length, in which the head enters five times. The eye 

 is circular and moderate in development, contained a little over four times in 

 the length of the side of the head. The upper margin of the dorsal fin is sub- 

 convex ; its anterior margin is nearer the tip of the snout than the insertion of 

 the caudal fin. The caudal is concave posteriorly ; the anal narrow and deep ; 

 the ventrals are inserted opposite the fifth ray (or third developed one) of the 

 dorsal, and their tips do not extend as far baclc as the tips of the posterior 

 rays of the dorsal fin when bent along the dorsal line. 



D 13 ; A 10 ; C 4, 1, 8, 8, 1, 3 ; V 9 ; P 15. 



The scales are sub-elliptical in general shape, presenting no grooves upon their 

 lateral sections, but few upon the anterior section, and numerous posteriorly 

 upon that section of the scale that is exposed. 



The specimens were collected by H. B. Mollhausen, in Coal creek, a tributary 

 of the South Fork of the Canadian river j along the R. R. route explored by Lt. 

 A. W. Whipple, U. S. A. 



2. MoxosTOMA KENNERLii. lu its general physiognomy this species resembles 

 31. ohlongiim more than any other of its genus. The greatest deptli, taken im- 

 mediately in advance of the dorsal fin, does not enter quite four times and a half 

 in the total length. The head forms a little less than the fifth of that same 

 length. The anterior margin of the dorsal is much nearer the tip of the snout 

 than the insertion of the caudal ; the upper margin of that fin is sub-convex and 

 as long as high, whilst in M. daviformis the height is much greater than the 

 length. The caudal is deeply concave posteriorly ; the anal is deep and narrow, 

 its extremity extending, as usual in the genus, to the base of the caudal. 

 The ventrals have pretty much the same position as in the preceding spe- 

 cies. 



D 14; A 10 ; C 4, 1, 8, 8, 1, 3; V 10; P 13. 



The anterior two rays, in both the dorsal and anal fins, ai'e mei'e rudiments; 

 also the anterior one in the ventral fins. The scales are not quite so long as in 

 the preceding species. The lower lip is rather broad and very little emarginated, 

 whilst in M. daviformis it is very thin and quite sub-divided. 



This species was caught in Dry creek, near Victoria, Texas, by Dr. 0. B. 

 Kennerly, under Major W. H. Emory, U. S. Commissioner of the U. S. and Mexi- 

 can Boundary line. 



3. MoxosTOMA VICTORIA. Form elongated, fusiform, reminding us, by its 

 general appearance, of certain species of Mullet (Mi/ffil). The greatest depth is 

 nearly equal to the length of the head, which constitutes the fifth of the entire 

 length, the lobes of the caudal fin excepted. The dorsal fin is higher than long, 



