130 BULLETIN 84, UNITED STATES NATIONAL MUSEUM. 



Albatross station 2667. June 5, 1886. Lat. 30 55' N.; long. 79 42' 30" W.; 

 273 fathoms; gy. s. bk. sp.; temp. 48.7 F. One specimen. 



Albatross station 2668. June 5, 1886. Lat. 30 58' 30" N.; long. 79 38' 

 30" W.; 294 fathoms; gy. s. dd. co.; temp. 46.3 F. Three specimens. 



All the specimens are very small and the diameter of the disk ranges between 

 2.5 and 5 mm. They agree with the two specimens which the Princesse Alice 

 gathered in 1902 at latitude 36 N. and longitude 26 W., but as the arms of the 

 latter, which were, besides, mostly incomplete, were not at all or very little rolled 

 up, I referred these two specimens to the genus Ophioplus, taking as a basis chiefly 

 the division of the upper brachial plates. A study of the specimens from the 

 Albatross, wjiich are more numerous and better preserved than those of the Princesse 

 Alice, and above all, a comparison with the species I have just described under 

 the name of Ophiochondrus granulatus, have permitted my settling the generic 

 position of 0. armatus, and completing on several points my former description. 



The disk is more or less strongly excavated in the interradial spaces. The 

 upper face is generally depressed in its center as well as in the interradii, while the 

 radial parts are protruding, and at the margin of the disk they are placed on a 

 higher level than that of the insertion of the arms. There are sometimes to be seen 

 radial ribs which succeed the radial shields toward the center of the disk, but this 

 arrangement is not constant. The upper face of the disk is covered with thin 

 imbricated plates, with very plain outlines; each of these plates shows a granule 

 which is now short and rounded, now a little elongated, but which as a rule is not 

 very high in the American specimens; these granules are generally rather scattered 

 and their surface is smooth. However, in the sample from station 2667, they are 

 more numerous and stronger and are elongated into small conical stumps the 

 end of which bears a few spinules which are extremely short. But these elon- 

 gated granules hardly deserve the name of spines. On the two examples from the 

 Princesse Alice, these stumps, which are rather numerous, are more elongated 

 than on the American specimens; they may be conical and pointed, or then 1 end 

 may be obtuse and provided with a few spinules, but I must say that they are 

 less elongated than shown in the drawings which I published in 1909, and where, 

 in spite of my corrections, their length remained exaggerated. On all the specimens, 

 I perceive radial shields, but these are small, very broadly separated and they have 

 on their margin a few granules. 



The under face of the disk is covered with distinct, rounded, nonimbricated 

 plates, which bear, chiefly near their margins, granules or small spines which 

 sometimes extend as far as the mouth shields. The genital slits extend as far as 

 the margin of the disk. 



The mouth shields are triangular, wider than long, with more or less conspicuous 

 lateral angles, which sometimes are but slightly rounded; the distal side is always 

 very convex on the American examples, and it shows in its middle a little lobe which 

 is fairly well marked. The adoral plates, which are crescent-shaped, are generally 

 less thick than on the two specimens from the Princesse Alice. 



The oral papillas amount to only three on all the American specimens, and only 

 on the two specimens of the Princesse Alice do they reach the figure four, which I 

 have again ascertained. The odd dental papilla is large and thick. 



