328 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
C. laeviuscula attenuata. Disc small; rays long and slender, 
flattened below. II = 5-6 r. 
Cribrella spiculifera sp. nov. Plate 2. 
Rays 5. R : r : : 04 mm : 14, or 77 mm : 15. R = 5 r. Breadth of ray near 
base about 19 mm. Rays somewhat tumid near base, but tapering quite rapidly 
to a rather attenuate tip ; somewhat narrowed at base, and with rather deep 
interbrachial sulci. Plates of abactinal surface rather large and not closely 
crowded, the groups of papulae being much more numerous than in C. laevi¬ 
uscula or oculata. The plates are irregularly rounded, or crescentic with the 
concave side toward the centre of the disc. They are irregularly scattered and 
show no evidence of arrangement in rows, except along the sides of the rays, 
where they assume a longitudinal arrangement. Near the tip of tire ray, on 
each side, are 3 longitudinal rows, the lowest of which consists of small plates 
lying close to the adambulacral plates and running parallel to that series the 
whole length of the ray. The two other rows consist of larger plates, and the 
lower of the two runs the whole length of the ray parallel to the row of small 
plates. The upper one, however, diverges from the lower about the middle of 
the ray and runs upward toward the abactinal side of the disc, where it joins 
the corresponding row of tire next ray. The narrow triangular space between 
this upper row and the lower one is filled by 3 or 4 short irregular rows of 
somewhat smaller plates. Toward the tip of the ray the plates of the 3 
longitudinal rows are arranged in more or less regular transverse series, but this 
arrangement is wanting near the base of the ray. Spinelets very numerous on 
all the abactinal plates, rather longer and more slender than in laeviuscula , 
measuring .3 mm. in length. The abactinal plates are so much less crowded 
and the spinelets are so much more numerous and slender than in laeviuscula 
that the surface does not appear granular, as it does in that species. Adambul¬ 
acral plates (Plate 4, fig. 1) with a single, stout spine, .75 mm. long, high up in 
the groove, and with 25-30 spinelets on the actinal surface. These spinelets are 
arranged in 6 or 7 series parallel to the ambulacral furrow, with 3 or 4 spinelets 
in each series. The spinelets on the edge of the furrow are largest, measuring 
2 mm. in length, and each successive series consists of smaller ones, the last 
series being very small. They are all closely crowded together. Madrepore 
plate single, small (2-3 mm. in diameter), covered with spinelets arranged in 
10-12 rows, radiating from the centre. Color of alcoholic specimens, uniform 
dark gray, with a slight yellowish tinge in some lights. 
There are two large specimens of this new Cribrella which is so 
different from the preceding species, but again we are confronted 
by the absence of data as to where and at what depths they were 
collected. This species does not seem to be related very closely to 
any previously known one, being easily distinguished by the large 
number of spines on the adambulacral plates. In size and gen¬ 
eral form it resembles C. obesa Sladen from the Straits of Ma¬ 
gellan, while in the armature of the adambulacral plates, C. com- 
