2694 Bulletin 4.7, United States National Museum. 



Monochirus, KAUP, Archiv fur Naturgsch. 1858, 94 (macuUpinnis) ; not of RAFINESQUE. 



1814, a genus of Soleince. 



? Aseraggodes, KAUI>, Archiv fur Naturgsch. 1858, 103 (guttulata). 

 jBaiostoma, BEAN. Proc. IT. S. Nat. Mus. 1882, 413 (braehiale). 

 Bceostoma, JORDAN & GILBERT, Synopsis, 965, 1883 ; amended orthography. 



Eyes and color on the right side. Body oblong, bluntly rounded ante- 

 riorly. Head small; eyes small, close together, the upper eye in advance 

 of the lower, the two separated by a bony ridge; mouth small, somewhat 

 turned toward the colored side; nasal flaps present, the nostril of the 

 blind side fringed ; lip of the colored side fringed ; teeth very small, on blind 

 side only; gill openings rather narrow, but confluent below, not reduced 

 to a slit; the branchiostegal region scaled. Head closely scaled every- 

 where, the scales on the colored side similar to those on the body, those of 

 the nape and chin much enlarged; scales on the blind side anteriorly with 

 their pectinations more or less produced, forming cirri; scales of both 

 sides extremely rough, extending on the lins. Lateral line straight, sim- 

 ple; edge of preopercle covered by the scales. Dorsal beginning on the 

 snout, low in front and thickly scaled, its rays divided; anal flu similar, 

 without spine; caudal fin free, convex; caudal peduncle very short and 

 deep ; pectoral fin of left side wanting, that of right side small or obso- 

 lete; ventral rays 3 or 4, the ventral fin of the colored side long, connected 

 with the anal by a membrane. This strongly marked genus contains 

 numerous species, all very closely related, and nearly all American. It has 

 been united by Dr. Giinther with Solea, but for no good reason, as the 

 number of vertebrae is very much fewer than in the European soles, and 

 the right ventral fin is decurrent along the abdomen and united with the 

 anal in the American soles, while it is short and wholly free in all the 

 European forms. The 2 groups belong in fact to distinct subfamilies. It 

 is also worth noticing that the name Achlrns is prior in date to that of 

 Solea. The species with rudimentary pectoral fins have been set apart by 

 Dr. Bean to form the genus Baiostoma, but the very slight development of 

 these organs in some of the species and the evidently very close relation- 

 ship of them all lead us to regard Baiostoma as a subgenus only. If we 

 follow Kaup in restricting the name Achirus to the Asiatic group called 

 Pardachirus, the present genus would receive the name of Trinectes. It 

 seems to us, however, that both Lacepede and Cuvier regarded the species 

 called by usfasciatus as the type of their genus Achirm. (axeip, without 

 hands; without pectoral fins.) 



BAIOSTOMA (/3ai6?, small; aro^a, mouth) : 

 a. Pectoral fins small, present at least on the right side. 



b. Pectoral fin present on hoth sides, that of the left side rudimentary, of a single 



ray; that of the eyed side with about 3 rays. 



c. Dorsal rays 60 to 67; anal rays about 48; scales 80; depth If in length. 



Color brownish, irregularly spotted with darker, and with about 10 



black vertical lines crossing the lateral line. ACHIRUS, 3065. 



cc. Dorsal rays 53 to 57 ; scales 75 to 80; depth Ig in length; scales not very 



rough, those of colored side with scattered, hair-like appendages, 



some black, others pale. Color olivaceous; head, body, dorsal, and 



anal fins covered with a network of dark lines; traces of about 8 



dark cross streaks sometimes present. INSCRIPTUS, 3066. 



