214 THE VOYAGE OF H.M.S. CHALLENGER. 
name implies, really consists, either wholly or partially, of united basals, the composition 
of the calyx is the same as in Holopus and Cyathidiwm, in fact as in most Neocrinoids, 
few of which are dicyclic. In all cases of which we have full knowledge, the basals rest 
upon something representing a stem, the special organ which is so characteristic of the 
Crinoids. It may perhaps be only a central abactinal plate, which becomes ‘transformed 
into an expanded disk of attachment, as in the Pentacrinoid larva of Comatula. But I 
strongly suspect on general morphological grounds that the basal element im the cup of a 
Crinoid does not come into direct contact with the supporting surface ; and I have an 
equally strong suspicion that it is never entirely absent. The radials of all Crinoids, 
excepting the ordinary Comatulz, rest in fossee which are separated by interradial ridges 
that mark the median lines of the united basals (Pl. XX. figs. 2, 3). Such ridges occur 
in Cotylecrinus, the raised angles of the upper edge of the cupule being interradial im 
* and I-am therefore disposed to agree with Zittel in regarding them as belong- 
ing to basals, the lower limits of which are as yet unknown. 
There is another character, besides the symmetrical radials, in which Cotylecrinus 
resembles Cyathidium. This is the association of two or more individuals ina manner 
suggestive of a process of budding, both internal and external. Steenstrup noticed this 
peculiarity in Cyathidium, and de Loriol has described it in Cotylecrinus miliaris.” This 
last species is further remarkable from the fact that the outer surface both of the cup and 
of the second radials found associated with it, ‘‘ est couverte de petites pustules, tantédt un 
position ; 
peu écartées, tantdt, au contraire, trés serrées.” These at once recall the blunt tubercles 
of Holopus (Pls. I., II.). 
Cotylecrinus, Cyathidium, and Holopus are evidently very closely allied, though the 
two former differ from the latter in the symmetry of their radials. 
In the remarkable form, which after having been referred to Plicatocrinus and also 
to Eugeniacrinus, has been made the type of a new genus Hudesicrinus by de Loriol, 
there are, however, five asymmetrical radials. These rest “sur une base large, assez 
élevée, adhérente par un épitement aux corps soumarins. Cette base n’est point une 
piece centro-dorsale semblable a celle des Cotylecrinus, renfermant les parties molles de 
animal, c’est un simple support.” The radials of this type are much higher than those 
of Cotylecrinus, and enclose a less extensive space in the centre of the funnel which they 
form by their apposition. It narrows considerably below, however, and I question very 
much whether it contained more than quite a small portion, if any, of the digestive 
canal. But according to de Loriol® “ c’est donc dans la cavité formée par les piéces radiales 
que se trouvaient logées les parties molles de l’animal.” I suspect, however, that the greater 
part of the visceral mass lay above the surface of the cup, and was protected by the two 
outer radials and lower arm-joints, just as in Rhizocrinus and Bathycrinus (PI. VII. 
figs, 2)3:; Pl LX. figs ie eel x fio: 20), 
1 Paléont. Frang., loc. cit., pl. 20, figs. 1, 2, 5, 6. 2 [bid., p. 204, pl. 19, figs. 15, 17. 5 Ibid., p. 98. 
