152 



BULLETIN 75, UNITED STATES NATIONAL MUSEUM. 



covered with scales. Genital slits short. Oral shields very broadly 

 oval, much wider than long. Adoral plates unusually large and 

 conspicuous, meeting broadly within, about twice as long as wide; 

 oral plates, correspondingly large. Oral papillae, two on a side, one 

 small, thick, rounded, at apex of jaw, the other small, flat, some- 

 what triangular, on adoral plate; scales of first oral tentacle pores 

 very wide and flat, but low and truncate, meeting each other across 

 the mouth slits so as to tightly close the mouth. First under arm 

 plate elongated (so that mouth slits are short), much longer than 

 wide, narrow at inner end, but rather abruptly widened near middle, 

 and gradually narrowed a little at distal end; succeeding plates 

 somewhat hexagonal or heptagonal, with rounded corners, and 

 lateral sides concave, about as wide as long, rather broadly in con- 

 tact. Side arm plates low and long, not meeting either below or 

 above; each one carries three stout spines, thick at base but taper- 



FIG. 62. AMPHIUEA PYCNOSTOMA. x 12. a, FROM ABOVE; b, FROM BELOW; c, SIDE VIEW OF THREE 



ARM JOINTS NEAR DISK. 



ing rapidly to a sharp point; middle one longest and about as long 

 as joint. Tentacle pores large, but the single tentacle scale is very 

 small. Color (dried from alcohol), disk, very pale gray, arms 

 whitish. 



Locality. Albatross station 4972, off eastern Japan, lat. 33 25' 45" 

 N.; long. 135 33' E., 440 fathoms, brown-green mud, foraminifera, 

 bottom temperature 39.8, 1 specimen. 



Type. Cat. No. 25641, U.S.N.M., from station 4972. 



Although this specimen is probably young and is unique in the collec- 

 tion, it seems best to make it the type of a new species on account of 

 the remarkable mouth parts, which are unlike those of any Amphiura 

 I have ever seen. The peculiarly stout arm spines and large tentacle 

 pores, each with a very small scale, are additional diagnostic char- 

 acters. 



