ATELECRINUS BALANOIDES. 481 



The middle o r 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" (18S8, 1. a). 



Atelecrinus balanoides Carp. 1881. 

 Tafel 14, Fig. 1,2,4, <?, 7. 



1881. P. H. Carpenter, Bull. Mus. Comp. Zool., 9, p. 16, pi. 1, fig. 1-6. 



1882. P. H. Carpenter, Linn Soc. Journ. Zool., 16, p. 489. 

 1888. P. H. Carpenter, Chall. Rep., 26, p. 70, pi. 6, fig. 6, 7. 



1879. Antedon cubensis Pourtales (pars), Bull. Mus. Comp. Zool., 5, p. 214. 



Material unci Fundorte (nach Carpenter, 1882, 1. 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. 

 " " 260. Off Granada. 291 Faden; feiner grauer Schlamm. Zwei Exemplare. 



Von diesem Material wurden mir liberwiesen: 



1) ein Exemplar von St. 151 (das von Carpenter, 1. c, 1881, pi. 1, fig. 1 abgebildete) und 

 mehrere Armbruchstucke. 



2) ein junges Exemplar von St. 150. 



3) ein Exemplar von St. 260. 



Carpenters Beschreibung (1. c, 18S8) lautet: 



"Centrodorsal acorn-shaped reaching 5mm. high by nearly 3,5mm. in diameter. It bears 

 five vertical double rows of eirrus 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 

 a very 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 



