46 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 
38._UR0L.0PIIUS Muller & Henle. 
Round Sting Rays. 
(Miiller & Heule, Plagiostomen, 1837, 173 : type Urolophns aarantiacns MUller & Henle 
— Eaia crnciata Lac('pede.) 
Disk oval or rhombic, the length and breadth not very unequal. 
Snout rounded or slightly prominent. Skin smooth or somewhat prickly. 
Tail rather short, little if any longer than the disk, muscular, provided 
with a distinct rayed caudal fin 5 no dorsal tin. Upper part of the tail 
with a strong serrated spine. Warm seas. Size small, {obgd, tail; 
^6<p(j~j crest.) 
* Skill perfectly suiootli. 
58. P. Siallci-i Cooper. 
Disk nearly round, a little broader than long, with the anterior mar- 
gins straightish, meeting in a slight angle. Snout (from the eyes) longer 
than the width of the interorbital space. Tail somewhat shorter than 
the disk. Skin without spines or prickles. Color light brownish, wHh 
marblings and wavy lines of yellowish and dusky, sometimes with 
yellowish spots, occasionally with wide, obscure dusky streaks, which^ 
are crossed by similar transverse streaks. Belly yellowish tinged. 
Coast of California, from Point Concepcion southward ; exceedingly 
abundant in sheltered bays. L. 12. The smallest of our sting rays. 
Closely related to the Australian U. cruciatns, if not identical with it. 
(Copper, Proc. Calif. Ac. Nat. Sci. iii, 95.) 
3fj._pXEROPL.ATEA Miiller & Henle. 
(Miiller A Henle, Plagiostoiiieu, 1837, 168: type liaia altaveUi L.) 
Disk much broader than long, its anterior margins meeting 111 a very 
obtuse angle, its outer angles more or less acute. Tail very short and 
slender, shorter than the disk, without liu, usually armed with a small 
serrated spine. Skin smooth or very nearly so. Size moderate or rather 
large. Warm seas, (-rs^a, fins ; TrAar^a, broad ; izreponXaTtia, an ancient 
name of R. altavela.) 
‘^Spiracle vritliout tentacle. 
59. P. (Le Sueur) Miiller & Henle . — Biitterjiij Bay. 
Disk scarcely twice as broad as long, covered with perfectly smooth 
• skin. Tail about one-third as long as the disk, with a very slight der- 
mal fold above and below. Snout a little projecting, so that the anterior 
edge of each pectoral is somewhat concave. Color brownish olive, 
finely marbled with grayish, and finely speckled. Anterior edge of disk 
