178 BULLETIN" 100, UNITED STATES NATIONAL MUSEUM. 



mouth shields smaller, the under arm plates broader, and the upper 

 arm plates of different shape. It can not be confused with A: luc- 

 tator, which I have described below, as the latter has only three arm 

 spines. 



AMPHIOPLUS LUCTATOR, new species. 



Plate 68, figs. 1-3. 



Localities. — Albatross station 5339 ; Palawan Passage ; Cauayan Is- 

 land (N.) bearing S. 59° E. 18.53 kilometers (10 miles), distant 

 (lat. 11° 22' 00" N., long. 119°) ; 95 meters (52 fathoms) ; Decem- 

 ber 20, 1908 ; M. 



One specimen (Cat. No. 41157, U.S.N.M.) 



Albatross station 5358; Jolo Sea; Sandakan Light bearing S. 34° 

 W. 36.51 kilometers (19.7 miles) distant (lat. 6° 06' 40" N., long. 

 118° 18' 15" E.) ; 71 meters (39 fathoms) ; January 7, 1908; M. 



One specimen (Cat. No. 41158, U.S.N.M.). 



Description. — Both of the specimens are of almost the same size, 

 and both have the disk torn away; the part of the disk which re- 

 mains has a diameter slightly more than 4 mm. The arms are all 

 incomplete; one of them is preserved for a length of more than 80 

 mm. ; they must have been very long. 



The radial shields are very large, and a little longer than broad. 

 In the specimens from station 5358 (fig. 1) they are pentagonal, 

 with an acute proximal angle bounded by two elongated sides, which 

 pass over two rounded angles into the two lateral sides which are 

 almost straight, a little shorter than the preceding, and which con- 

 verge slightly toward the narrow and straight distal side ; it is at the 

 level of the rounded lateral angles that the shield reaches its max- 

 imum width. In the specimen from station 5339 (fig. 3) these shields 

 are relatively a little more elongated and narrower, and the distal 

 border is rounded; that is the only difference which I find between 

 these two specimens. The adoral plates are large and rather broad, 

 tapering inwardly, though in contact by a narrow border in the 

 median interradial line; they are much broadened outwardly, and 

 they may even touch those adjacent in the radial line, in such a way 

 as to form an almost continuous ring. In the specimen from station 

 5358, this ring is completely closed, all the adoral plates touching 

 their neighbors, while in that from station 5339 this ring is not quite 

 complete, and the adoral plates are separated by an extremely narrow 

 space, within which is included the first under arm plate. The oral 

 plates are not very high, being almost as high as broad. The lateral 

 mouth papillae are four in number; the innermost is thick, conical, 

 and short; the second, inserted on the oral plate, is rectangular, 

 almost as long as broad, with the free border convex ; the third, which 

 is the most developed, arises from the angle between the oral and 



