22. MYLIOBATID..E RHIXOPTERA. 
51 
G7. M. fresiBHEavillei Le Sueur. 
Disk broader than long, the breadth equal to the length of the tail. 
Skin entirely smooth. A blunt, whitish promineuce over each eye. 
Muzzle prominent. Teeth of the main row 4 to 0 times broader than 
long ; small teeth in three rows. Eeddish brown. Tail nearly black. 
Cape Cod to Brazil ; not uncommon. 
(Lo Sueur, .Touru. Ac. Nat. Sci. Phila. iv, 111: Mjiliohatis hispinosus Dum6ril, Hist. 
Nat. Poiss. 637: Mi/liobaiis acuta Stover, Hist. Fish. Mass. 215.) 
68. M. caSafoa’BliCBas Gill. — California Sting Bag; Batfisli. 
Disk not quite twice as broad as long ; the wings anteriorly convex, pos- 
teriorly somewhat concave. Cephalic fin very blunt, nearly 4 times as 
broad as long. Tail nearly twice as long as the disk. Ventral large, 
broader than long. Lateral teeth in 3 to 5 series on each side; median 
teeth only 3 to 4 times as broad as long, even in the adult. Skin wholly 
smooth. Color dusky brownish, the young somewhat variegated. San 
Francisco southward ; very common on the Pacific coast. 
(Bldnoptera vespertilio Girard, Boston Journ. Nat. Hist. 18.57, 544: Holorliinus vespcr- 
iilio Gill, Proc. Acad. Nat. Sci. Phila. 1862, 331 (not Mgliobatis vespertilio Bleeher); 
Gill, Ann. Lyc. Nat. Hist. N. Y. 1865, viii, 137.) 
43.— RHIWOPTERA Kuhl. 
CoiD-nosed Bays. 
(Kuhl, Miiller, Ahhandlungen Ak. Wiss. Berl. 1836, 237 : type Bhinoptera hrasiliensis 
Muller = Mgliobatis jussieui Cuvier.) 
Disk broader than long, with the anterior angles more or less acute. 
Snout more or less emarginate on the median line. Cephalic fin emar- 
ginate and placed on a plane below the level of the pectorals, the snout 
thus appearing four-lobed. Free border of the nasal valve not emar- 
ginate. Teeth in 3 to 20 rows, the median teeth more or less enlarged, 
but often smaller than in Myliolgatis. Tail long, whip-like, with a small 
dorsal fin and a serrated sjune. Troi^ical seas. (,ob, snout ; Tzrspdv, fin.) 
69. R. «j«aadtt’il©toa (Le Sueur) Cuvier. 
Disk one-third broader than long ; anterior boi’ders almost straight, 
posterior undulated ; muzzle deeply emarginate. Teeth in seven rows, 
the median teeth four times as broad as long. Tail very slender, a lit- 
tle longer than the disk. Skin smooth or nearly so. Color brownish. 
Cape Cod to Florida ; not rare. Attains a large size. 
(Baia qnadriloba Le Sueur, Jouru. Ac. Nat. Sci. i, 44; Giiutber, viii, 494; Dum^ril, 
Hist. Nat. Poiss. i, 648. 
