162 BULLETIN 75, UNITED STATES NATIONAL MUSEUM. 



thickest of all. First under arm plate minute, but very distinct, 

 longer than wide; succeeding plates squarish and broadly in contact, 

 soon becoming pentagonal and narrowly in contact. Side arm 

 plates small, not meeting above or below, at least at base of arm; 

 each plate carries four, or rarely five, slender, very acute spines, of 

 which the third or fourth is distinctly hooked at tip and microscop- 

 ically serrate, and the fourth or fifth (lowest) is the longest, slightly 

 exceeding the joint. Tentacle scales two, distinct if not large. Color 

 (dried from alcohol), disk, grayish; arms, pale brownish or nearly 

 white. 



Localities. Albatross station 3698, off Manazuru Zaki, Honshu 

 Island, Japan, 153 fathoms, green mud, volcanic ashes, sand, 16 

 specimens; station 3713, off Ose Zaki, Honshu Island, Japan, 45 to 

 48 fathoms, volcanic sand, shells, rocks, 2 specimens; station 3739, 

 off Ose Zaki, Honshu Island, Japan, 55 to 65 fathoms, volcanic sand, 

 shells, rocks, 21 specimens; station 4817, Sea of Japan, lat. 38 12' 

 N. ; long. 138 52' E., 61 fathoms, fine gray sand, bottom temper- 

 ature 51.9, 1 specimen; station 4965, off eastern Japan, lat. 33 

 25' 20" N.; long. 135 10' 50" E., 191 fathoms, dark green-gray sand, 

 shells, bottom temperature 49.4, 3 specimens; station 5091, Uraga 

 Strait, lat. 35 4' 10" N.; long. 139 38' 12" E., 197 fathoms, green 

 mud, coarse black sand, pebbles, bottom temperature 47.6, 2 spec- 

 imens; station 5092, Uraga Strait, lat. 35 4' 50" N.; long. 139 38' 

 18" E., 70 fathoms, coarse black sand, bottom temperature 56.3, 

 5 specimens. Bathymetrical range, 45 to 197 fathoms. Temper- 

 ature range, 56.3 to 47.6. Fifty specimens. 



Type.C&t. No. 25601, U.S.N.M., from station 3698. 



This is one of those perplexing species which link AmpJiiodia and 

 Amphioplus so closely that the latter will have to be redefined if not 

 abandoned. In the present species there are certainly four oral 

 papillge on a side, but the fourth (outermost) is so much smaller than 

 the others that, in view of its other characters, I prefer to keep 

 ancistrota in AmpJiiodia for the present. There may be more than 

 one of the arm spines in each group hooked at the end, but as a rule 

 there is only a single one and that only on the basal part of the arm. 

 The upper arm plates and the tentacle scales taken in connection 

 with the arm spines will serve to distinguish this species. 



AMPHIODIA DIGITULA, new species.a 



Disk 6 mm. in diameter; arms about 35 mm. long, probably. 

 Disk covered by a close coat of numerous scales, of which those at 

 the center are the largest and those at the interradial margins are 

 very minute; the primary plates are scarcely distinguishable. Radial 



a Digitulus (dim. of digitus), signifying a little finger, in reference to the finger-like 

 processes on the spines borne by the genital scales. 



