ANALYSIS OF SPECIES OF MYXOSTOMA. 11.5 



ANALYSIS OF SPECIES OF MYXOSTOMA. 



Lips distinctly plicate, 

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



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

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

 3f to 4i 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 tin high and large, larger than in anj 

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

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



fins white OARPIO, 3. 



bb. 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 loss 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. 



ee. 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 macrolepidotum, 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 .'30-6: back with much smoky 

 shading lachrymak. 



