ATELECRINUS BALANOIDES. 481 
The middle o° each basal rests on the top of one of the interradial ridges of the stem. In older 
individuals, however, just as in the Antedon-larva the amount of the first radials which is visible 
on the exterior of the calyx becomes relatively less and less, and the same is the case with the 
basals. These are best described as triangular, with their lower angles extended so as to meet 
those of their fellows, and separate the radials from the centrodorsal by what is practically little 
more than a line, only visible at all under specially favorable conditions of light. Each of the 
basals, when isolated, has the form of a short triangular prism with a flattened plate-like exten- 
sion of each side. They are in complete lateral contact, so as to form an unbroken ring on the 
under surface of the radial pentagon, very much as in Pentacrinus alternicirrus or in Pentacrinus 
wyvilli-thompsoni. Atelecrinus cubensis has comparatively large basals which are of nearly 
uniform height (0,5mm.), all round the calyx, rising very slightly at the interradial angles; 
while in Atelecrinus wyvilli each basal is slightly arched, with its apex interradial, and it is only 
in contact with the outer edge of the centrodorsal at the interbasal sutures” (1888, |. ¢.). 
Atelecrinus balanoides Carp. 1881. 
Tafel 14, Fig. 1, 2, 4, 6, 7. 
1881. P. H. Carpenter, Bull. Mus. Comp. Zodl., 9, p. 16, pl. 1, fig. 1-6. 
1882. P. H. Carpenter, Linn Soc. Journ. Zoél., 16, p. 489. 
1888. P. H. Carpenter, Chall. Rep., 26, p. 70, pl. 6, fig. 6, 7. 
1879. ‘Antedon cubensis Pourtalés (pars), Bull. Mus. Comp. Zodl., 5, p. 214. 
Material und Fundorte (nach Carpenter, 1882, |. c.): 
Blake Station 43, 24° 8’ N., 82°51’ W.; 339 Faden. Ein Exemplar. 
150. Zwischen St. Kitts und Nevis. 373} Faden. Schlamm und grobe Stiicke. 
Zwei Exemplare, von denen eins jung. 
. “151. Off Nevis. 356 Faden. Zwei Exemplare. 
? “22. ~=Off St. Lucia. 422 Faden. Ein Exemplar. 
i “260. Off Granada. 291 Faden; feiner grauer Schlamm. Zwei Exemplare. 
Von diesem Material wurden mir iiberwiesen: 
1) ein Exemplar von St. 151 (das von Carpenter, |. c., 1881, pl. 1, fig. 1 abgebildete) und 
mehrere Armbruchstiicke. 
2) ein junges Exemplar von St. 150. 
3) ein Exemplar von St. 260. 
Carpenters Beschreibung (I. c., 1888) lautet: 
“Centrodorsal acorn-shaped reaching 5mm. high by nearly 3,5mm. in diameter. It bears 
five vertical double rows of cirrus sockets, the upper ends of which are separated by more or less 
distinct interradial ridges. Four to six sockets in each row, the dorsal pole, though rough, being 
free from functional sockets. The ends of their horseshoe-shaped rims slant downwards and out- 
wards, but are much more prominent in some individuals than in others. 
“The cirri have three or four quite short, almost triangular basal joints. The next is two or 
three times as long as wide, and its successors are much elongated, reaching 2,5mm., with a slight 
tendency to overlap one another on the ventral side of the cirrus. There are probably about 
_ thirty-five joints, the length much exceeding the breadth, till the penultimate, which is followed by 
_ avery small terminal claw. The last six joints taper rapidly. 
“The basal ring is a very thin plate, rising at the interradial angles into triangular elevations, 
¢ - Which are produced slightly outwards and rest upon the upper ends of the interradial ridges of 
