062 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxvl 



species D. nvdus (Giinther), known by the smooth skin, is listed by 

 Blceker as from Japan, bnt no locality is given. 



Diinieril linds 2 buccal papilhv. 



(Named for INI. (ierrard.) 



41. PTEROPLATEA Muller and Henle. 

 P/<'roptaYfa MuLLER and Henle, Plagiostomen, 1838, p. 168 [altarela). 



Disk much broader than long-, its anterior margins meeting in a very 

 o))tuse angle, its outer angles more or less acute, the form, therefore, 

 transversely rhombic. Tail very short and slender, shorter than the 

 disk, without fin. armed with a very small, serrated spine, which is 

 often Avanling. Skin smooth, or very nearly so. Size rather large. 

 Warm seas. The species are closely related. ■ 



{Ttrepov, fin; rrXaTv;^ broad; an ancient name of Pteroplatea alta- 

 vela.) 



51. PTEROPLATEA JAPONICA (Schlegel). 



TSUBAKUROEI (SWALLOW RAY); YOKOSAEI (CROSS-WISE RAY). 



Pleroplalea japo)nca Schlegel, Fauna Japouica, Poiss., 1850, p. 309, pi. cxli; 



Nagasaki. — Bleeker, Act. Soc. Sci. Indo. Neerl., Ill, 1857, Japan, IV, 



p. 45. — DuMERiL, Elasmobranehes, 1870, p. 614. 

 Das^/cttix micrura rar. jnpo)tirnfi Gray, Chondropt., 1851, p. 122; Japan, Canton. 

 Pteroplatea hirundo, Ishikawa, Prel. Cat. 1897, p. 60; Tokyo, Boshu; (not of 



Lowe) . 



Disk very broad, its length onl}- a little more than half its width; its 

 greatest width would fall about opposite last fourth of its length. 

 Head very broad, and flattened; snout only a .small, blunt point, and 

 its length equal to two-thirds interorliital space; anterior margin of 

 disk broadly convex; eyes small, somew^hat elevated, T in inter- 

 or))ital space; nostrils large, well separated, with large flaps; mouth 

 moderate, equal to its length from tip of snout, undulate; teeth in 

 broad, pavement-like patches in jaws; interorbital space very broad, 

 flattened. Spiracles directly behind eye, much larger than the same. 

 Gill-openings moderate. 



Body entirely smooth. 



Base of ventral If in interor))ital space; tail very small, short, its 

 length about twice interorbital width; a small, weak spine on upper 

 surface of tail at its first third. 



Color in alcohol, olivaceous browni above, marked with very fine, 

 numerous, darker punctuations, tail whitish with eight dark rings 

 al)out as broad as interspaces; lower surface of body whitish. 



Length, 9i inches. 



Here described from a female from Wakanoura. 



Coasts of Japan, rather common. It was taken at Tokyo, Waka- 

 noura, Hiroshima, Hakata, Kawatana, and Nagasaki. 



