Family XXIII. Soleid^e. 235 



fins small or wanting. The species of this family are very numerous 

 in the warm seas, a few enter brackish, and still fewer inhabit fresh 

 waters. 



Subfamily Achirinae. 



90. Achirus Lacepede. 



Achirus Lacepede, Hist. Nat. Poiss., iv, 659, 1803. (Type, Achirus 

 fasciatus Lacepede.) 



Baiostoma Bean, Proc. U. S. Nat. Mus., 1882, 413. (Type, Baiostoma 

 brack iale Bean.) 



Body broad, bluntly rounded anteriorly; head small; eyes small, 

 close together; eyes and color on the right side; mouth small, mostly 

 developed on the right side; teeth small, on blind side only, gill open- 

 ings narrow ; scales ctenoid ; some scales on head and anterior part of 

 the body enlarged, some of those on' blind side with hair-like projec- 

 tions; lateral line straight, simple; dorsal fin beginning on snout; 

 ventral rays 3 or 4, the fin on colored side connected with the anal by 

 a membrane. 



KEY TO THE SPECIES OF ACHIRUS. 



a. Pectoral fin of right side only present. page 

 b. Pectoral fin with 4 rays; depth of body 1% 



in its length; scales 70 in lateral series mazatlanus 235 



bb. Pectoral fin with 2 rays; depth of body i| 



in its length; scales 85 in the lateral series fonsecensis 236 



aa. Pectoral fins wholly wanting; scales 66 to 75 fasciatus 236 



Subgenus Baiostoma Bean. 



225. Achirus mazatlanus (Steindachner). Mexican Sole. 



Solea mazatlana Steindachner, Ichth. Notizen, ix, 23, 1869; 



Mazatlan. 

 Solea pilosa Peters, Berliner Monalsber., 1869, 709; Mazatlan. 

 Achirus mazatlanus Jordan, Proc. Cal. Acad. Sci., 1895; Rio Pre- 

 sidio, Sinaloa: Jordan & Evermann, Bull. 47, U. S. Nat. Mus., 

 1898, 2698; Rio Presidio, Sinaloa. 

 Streams of Mexico which empty into the Pacific Ocean. 

 Head 3^; depth i%\ D. 56; A. 42; scales 70. Body broad, oval; 

 eyes small, the upper in advance of the lower; diameter of eye 7^2 in 

 head; interorbital % diameter of the eye; nostril in a tube, placed just 

 above the middle of the mouth; pectoral developed on the eyed side 

 only, with about 4 rays; origin of dorsal on tip of snout; scales of right 

 side with numerous black hair-like appendages. 



