428 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



of the arms, but they are more or less erect and consequently very 

 evident. 



The tentacle pores, which are very large, are each covered by two 

 large rounded scales, the external scale a little larger than the in- 

 ternal; these two scales persist throughout the whole length of the 

 arms. 



The coloration of the specimens in alcohol is yellowish. 



Affinities and distinctive features. — Among the species of Ophiozo- 

 nella which possess two tentacle scales throughout the whole length 

 of the arms this species, in the form of the mouth shields and the. 

 other mouth pieces, as well as by the presence of three arm spines,, 

 recalls especially Lyman's O. tessellata, but the arrangement of the 

 dorsal plates of the disk is different, the radial shields are smaller, 

 and they do not possess the large broadened and short spine on their 

 distal border in O. tessellata. 



The specific characters which I have described are always well 

 marked in all the specimens which I have been able to examine, 

 and they are already manifest in the smallest specimens. 



These youngest examples already show the same robust habitus as 

 the adults, and they also have thick and short arms; the upper 

 arm plates are quadrangular for a large part of the length of the 

 arms, the arm spines are thick and short, etc. This may be deter- 

 mined from a specimen from station 5114 in which the diameter 

 of the disk is only 8 mm. and of which the arms are 20 mm. long 

 (pi. 79, fig. 10). In a specimen from station 5305 the diameter 

 of the disk is 9 mm., and the arms are 25 mm. long. Another in- 

 dividual of considerable interest is that from station 5429 (pi. 79, 

 fig. 5). Its disk is only 6 mm. in diameter; the arms, which are 

 very broad at the base, are robust and taper rapidly, their length 

 not exceeding 17 mm. ; the first upper arm plates are quadrangular, 

 and their proximal angle, which narrows little by little, disappears 

 only toward the seventh or eighth segment. The arm spines are 

 thick and stout; they are sometimes three in number, but usually 

 two, even on the first arm segments. In this young specimen the 

 mouth shields are appreciably broader than in the larger; they have 

 exactly the form which I described in 1904 in O. molesta from the 

 single very young individual which I had at hand, which again 

 confirms the specific identity which I have seen fit to establish. 



OPHIOZONELLA SUBTILIS, new species. 



Plate 79, figs. 3, 4, 9, 11, 12. 



Localities. — Albatross station 5371 ; Marinduque Island and vicin- 

 ity; Tayabas Light (outer) bearing N. 43° W., 11.1 kilometers 

 (6 miles) distant (lat. 13° 49' 40" N., long. 121° 40' 15" E.) ; 



