ANALYSIS OF SPECIES OF MYXOSTOMA. 115 



ANALYSIS OF SPECIES OF MYXOSTOMA. 



Lips distinctly plicate. 



t Lower lip full, its posterior edge truncate, not infolded and " /^-shaped ". 



a. Species with the body distinctly compressed, the depth 3 to nearly 5 in length. 



6. Dorsal fin largely developed, its rays 15 to 18 in number : head rather large, 



3f to 4 in length, broad above : mouth large, with full lips : eye rather 



large : body deep, strongly compressed, the back somewhat elevated, the 



depth about 3 in length : dorsal fin high and large, larger than in anj 



other species of the genus, the first ray about as long as the base of thG 



fin : scales 5-43-4, quite large : coloration very pale and silvery, the lower 



fins white CARPIO, 3. 



66, Dorsal fin moderate, its rays 12 to 14 in number. 

 c. Scales large; 41 to 50 in the course of the lateral line. 



d. Caudal fin normal, the two lobes about equal and similarly colored. 

 e. Head singular in form, much shortened, the muzzle very abruptly de- 

 curved, descending almost perpendicularly in front of the eye : the 

 head wedge-shaped from behind forwards, and less so from below 

 upwards, its sides subvertical and the lower cross-diameter of the 

 head greater than the upper. 



/. Eye very large, more than one-third the length of the side of the 

 head (in an individual of six inches in length) : lips thin, very 

 faintly plicate : width of head through the opercles greater than 

 the thickness ot the body : head 4 in length ; depth about the 

 same : dorsal rays 13 : scales 6-43-5 : body shortish, closely com- 

 pressed, the back somewhat elevated, and the caudal peduncle 

 unusually long in proportion : color smoky-blue ; lower fins white : 



size probably small EURYOPS, 4. 



?. Head normal in form, not as above. 



g. Mouth moderate or large, not very small, nor very much overpassed 

 by the muzzle : lips thick, strongly plicate : body stoutish, vary- 

 ing to moderately elongate: dorsal fin medium, its developed 

 rays 12 to 14, usually 13 in number : scales large, about 6-45-5 : 

 lower fins in the adult red or orange. 



h. Head comparatively elongate, 4 to 5 in length : mouth large : 

 size very large, reaching a length of two feet 



or more MACKOLEPIDOTUM, 5. 



x. Head quite elongate, 4 to 4* in length : back little 

 elevated: body rather elongate, not greatly 

 compressed : scales pretty large, 6-42 to 49-5 : 

 back bluish or olive ; sides brilliantly silvery, 

 with bright reflections ; dorsal fin dusky above ; 



lower fins bright red ...duquesnii. 



xx. Head a little shorter, 4 to 4f in length : form 

 of the preceding: scales distinctly smaller, 

 7 or 8-48 to 50-6: back with much smoky 

 shading lacTirymale. 



