


















216 REVIEWS. 
joints. These joints are distinguished by two points of structure; first, 
that two articulated, branched ** radicles," or ‘‘ cirri,” branch off from the 
distal extremity of the third to the thirty-second lower joints, and from 
the very end of the lowest, attaching the stem to various marine objects, 
stalked **pentacrinoid" stage of Antedon (Alecto, Comatula). There 
appears, however, to be no voluntary mobility in the stalk, and the pur- 
pose of this structure is, probably, only to give it a greater passive flexi- 
bility, the lines of articulations alternating regularly at angles approach- 
ing to the right angle. The upper joints are the youngest, shorter and 
thinner, with the exception of the very uppermost (to whic h the basals 
ealed); it is e, obconical, and serves, as in somite Apio- 
crinus, etc., as the base of the calyx, d by the fourth, fifth, s or 
seventh series of **Radialia," three in each. Of seventy-five spec ché 
and seven 
h the soft 
The third 
qr radii were found in fifteen, five in Mem -three, six in fifteen, 
wo specimens; the radii are only connected together throug 
peristome. s The first *radiale" is not visible from without. 
adiale" 
wearing on every second joint a ‘‘pinnula” (six to sev , rarer 
eight, on either side, consisting of eleven to twelve, rarely fifteen joints). 
The mouth is central, the anal opening short, eccentric, interradial; the 
peristome of the disc is soft, but strengthened by small, microscopi 
(from four to seven) perforated plates; five of these are greater than 
others, and occupy the angles of the mouth; they are the “oral plates” 


of the pentacrinoid Antedon, disappearing at an early period in the adult. 
The mouth is provided with twenty (sixteen to twenty-eight) — 
longer and shorter, radial and interradial, pinnate, partly studded W 


. “vesicles,” so ik of Antedon, are nowh o! 
double series of scale-like plates closes the furrows, when the tentac 
| are withdrawn. ere are no ^ pinnules ovales." Inas mee 



nbranched rd of the men also confirms the 
fossil ticrinus had simple, 
recent 
