REPORT ON THE CRINOIDEA. 267 
In a considerable number of individuals from different localities on both sides of the 
Atlantic, I have found the radials to be marked by a circular furrow of variable depth. 
It crosses the body of the radial at the level of 
the upper angles of the basals between which 
the radial rests, as is well shown in the young 
specimen represented on Pl. LIIL fig. 8. 
binis = 
ia 
In the more mature individual from the 
Caribbean Sea, shown in PI. IX. fig. 3, the 
furrow crosses the radials at about half their 
height; while in one of the specimens from the 
neighbourhood of the Azores (Station 76) the 
basals are much less angular at the top, so that 
the radials are more nearly oblong and almost 
entirely above a rather strong constriction at 
the level of the basiradial suture (Pl. X. fig. 3). 
Other individuals, however, are entirely desti- 
tute of any indication of such a constriction. 
bi z : Fic. 19.—The calyx and arm-bases of two specimens of 
This is the case, for example, with those ence rawsoni from Panama-; x 4, In both cases 
i é the cup is unusually wide in proportion to its height ; 
dredged by Captain Cole off Panama, which and in the right hand specimen (B) the grouping of 
the lower brachials is very irregular, 
are further remarkable, not only for the great 
relative width of the basal cup as shown in the woodeut (fig. 19), but also for the extreme 
variation in the position of the first pinnule. 
In one individual this is on the epizygal of the seventh brachial in two arms, on that 
of the fifth in two others, and on that of the fourth in the remaining one. In four arms 
of another specimen the epizygals bearing the first pinnule are respectively those of the 
third, fourth, fourth, and fifth brachials ; while in a third individual three arms are normal, 
with a pinnule on the third epizygal, the two others not bearing a pinnule till the next 
(fourth) joint. Lastly, in a fourth individual every one of the arms is developed 
abnormally. Three of them are shown in woodcut, fig. 19,B. I will not attempt to 
offer an opinion upon the grouping of the syzygies and muscular articulations in this 
specimen. But in one arm at least there appear to be two syzygies in succession ; so 
that the composite brachial is in three parts instead of in two only. This is a variation 
of some interest, as it is normal in the arms of Hyocrinus (Pl. VI. fig. 1). Both types 
of brachial, that with one and that with two syzygies, occur in different species of the 
Paleozoic Heterocrinus, as pointed out already (ante, p. 58). 
Although the occurrence of Rhizocrinus rawsoni in the East Atlantic and its more 
striking peculiarities, especially the length of the basals, were noticed in the first Report 
upon the Caribbean Crinoids’ which Prof. Perrier quotes, he was led to describe the 
1 Bull. Mus. Comp. Zodl., vol. x., No. 4, p. 174. 
