96 BULLETIN 84, UNITED STATES NATIONAL MUSEUM. 



OPHIACANTHA V1VIPARA Ljungman. 



See for bibliography: 



Koehler(12), p. 138. 



Albatross station 2769. Jan. 15, 1888. Lat. 45 22' S.; long. 64 20' W.; 

 51.5 fathoms; gn. m. fne. s.; temp. 56.6 F. One specimen. 



Albatross station 2771. Jan. 17, 1888. Lat. 51 34' S.; long. 68 00' W.; 

 50.5 fathoms; gy. s. bk. sp. ; temp. 49.4 F. Eleven specimens. 



One specimen from station 2769 is provided with six arms ; all the others have 

 seven. The diameter of the disk ranges between 9 and 19 mm. In all of them 

 the upper face of the disk is covered with rounded granules except in the largest 

 one, the granules of which are] somewhat elongated and conical. None of the 

 specimens carries any young ones. 



OPHIACANTHA (OPHIOPRISTIS) PERMIXTA, new species. 

 Plate 11, figs. 3-4. 



Albatross station 2665. May 2, 1886. Lat. 27 22' N.; long. 78 07' 30" W.; 

 338 fathoms; fne. gy. s.; temp. 45.2 F. One specimen. 



Type. Cat. No. 32296, U.S.N.M. 



This single specimen is, unfortunately, in very bad condition; one part of the 

 upper face of the disk is lacking, and the latter has been stretched in one direction, 

 which has somewhat altered its shape; moreover, three of the arms are broken 

 on the level of their insertion on the disk, and are entirely lacking, the other two 

 being preserved only to a length of scarcely one centimeter. However, all the 

 characters of the species are very clear, and one can easily ascertain that they 

 do not refer to any known form. 



The diameter of the disk measures 1 3 mm. in one direction and about 1 mm. 

 in the other direction; the outline is pentagonal and the sides are almost straight. 



The upper face is covered all over with granules which are rounded, unequal, 

 rough, and very closely arranged; besides, between these granules, there are fairly 

 strong, elongated, conical, and pointed spines, the number of which is rather 

 important. The whole somewhat reminds one of the arrangement known in 

 Ophiolimna mixta (Lyman) or littoralis Kcehler; but here the granules He more 

 closely and the spines (the shape of which, by the way, is different) are much more 

 pointed. The underlying plates are completely invisible, and so are the radial 

 shields. But the covering of the upper face of the disk does not stop at the issue 

 of the arms, for the granules extend to a certain length of the upper face of the arms, 

 that is to say on four or five articles at least. But these granules, instead of remain- 

 ing rounded as they were on the disk, grow longer and become completely conical 

 and pointed; they are at least twice higher than wide, and they may henceforth 

 be called small spines. These pointed granules can not be compared with the 

 large spines of the upper face of the disk, which stop at the margin of the latter 

 and do not extend on the upper face of the arms. These little conical granules 

 first lie fairly close at the base of the arms; then they rapidly become few and far 

 between until they are finally lodged near the distal margin of the upper brachial 

 plates in the median part of the said margin. On the last article preserved they 

 amount to four, and I do not know on how much more of the arm they may occur. 



