612 THE VOYAGE OF H.M.S. CHALLENGER. 
the furrow, over which it is directed horizontally and not quite at a right angle to the 
axis of the plate, but directed very slightly aborally. Its length is about equal to half 
the width of the furrow, and it.is covered with a membrane so delicate and close fitting 
as to appear naked. Not more than one or two pedicellariz are present, and these are 
often wanting. The actinal spine is articulated on a small tubercular eminence near the 
middle of the actinal surface of the plate; it is about 1°5 to 2 mm. in length at 20 mm, 
from the base of the ray, delicate, cylindrical, rather robust at its base and tapering to a 
sharp point, and is invested with a delicate membranous sheath crowded with minute 
pedicellariz. The lateral spines are delicate, cylindrical, tapering, 3°5 to 4:0 mm. in 
length at 25 mm. from the base of the ray, and encased in a membranous sheath crowded 
with pedicellariz, and each is articulated on a small, triangular, rudimentary plate— 
the reptesentative of an infero-marginal plate. These small rudimentary plates are 
sutured to the adambulacral plates by the base of the triangle, and the lateral spine is then 
articulated on the aboral facet, the normal direction of the spine being consequently out- 
ward at an angle of about 45° to the axis of the ray, and this conspicuous little plate 
recalls in the most vivid manner the attachment of the pinnule of a Comatula. At the 
extreme base of the ray there are two of the rudimentary marginal plates (which Sars? 
named dorso-marginal) ; the first, which articulates on the so-called odontophore, is as long 
as the adambulacral plate on which it is superposed, whilst the next is very much smaller. 
I consider that these are the representatives of infero-marginal plates and not supero- 
marginal, as supposed by Sars 
a mistake which I would suggest has arisen from the 
adambulacral plate appearing at first sight to stand as an inferior marginal plate in rela- 
tion to these small plates. From the fact that the plates in question are attached to 
the adambulacral plates and the odontophore, and likewise when further out on the 
ray bear the lateral spine, it would, in my opinion, seem far more natural to rank 
them as the rudiments or representatives of infero-marginal plates than of supero- 
marginals. 
Colour in alcohol, a rather dark brownish grey, the ambulacral tube-feet being dark 
brown. 
‘ Locality. —Station 146. Between Marion Island and the Crozet Islands. December 
29, 1873. Lat. 46° 460” S., lone. 45° 31 0” E. Depth 1375 fathoms. Globigerina 
ooze. Bottom temperature 35°°6 Fahr. ; surface temperature 43°:0 Fabr. 
Station 147. West of the Crozet Islands. December 30, 1873. Lat. 46° 16’ 0”S., 
long. 48° 27'0" E. Depth 1600 fathoms. Diatom ooze. Bottom temperature 34°°2 Fahr. ; 
surface temperature 41°-0 Fahr. 
Rema rks.—Brisinga membranacea is remarkable for the extremely delicate and rudi- 
mentary character of the abactinal skeleton which is represented only by transverse bars 
On some remarkable forms of animal life from the great depths off the Norwegian coast, Part IL., 
University Program, Christiania, 1875, p: 9 
