REPORT ON THE CRINOIDEA, 213 
unquestionably very closely allied to it, but I am inclined to think that it would be 
premature to consider them all as congeneric. 
Two other fossil genera of Neocrinoids, Cotylecrinus and Eudesicrinus, both confined 
to the Lias, are nearly related to Holopus and Cyathidium, and should in my opinion be 
placed in the same family. This has been generally done with Cotylecrinus, which is 
perhaps better known by its older name of Cotylederma, Quenstedt. But Schliiter denied 
its relationship to Cyathidium,' which had been previously pointed out by Roemer? and 
Deslongschamps,’ on the ground that there are no perforated plates in Cotylecrinus. It 
is true that Quenstedt’s original specimens had no radials attached, and were therefore 
imperforate, as were most of those figured by Deslongschamps ; but the latter author also 
described and figured a fine specimen of Cotylecrinus docens, showing the large articular 
surfaces of the radials, and the openings of their central canals, just as in Cyathidium. 
This must surely have been overlooked by Schliiter, or he could scarcely have questioned 
the relationship of the two types. 
Both in Cotylecrinus and in de Loriol’s new genus Ludesicrinus, the radials rest wpon 
a more or less tubular structure which is slightly expanded below and has been variously 
described. In the former genus it has been called a stem by Quenstedt and by 
MM. Deslongschamps,* and a top stem-joint by Schliiter.’ Zittel® suggested that the 
upper part of it, which is marked by crests with intervening fossee for the reception of 
the radials, should be considered as composed of anchylosed basals, and that the lower 
part is a centro-dorsal ? De Loriol,’ however, considers the whole as a centro-dorsal piece, 
not having been able to find any trace of sutures separating the upper part from the 
lower. It is sometimes found in an isolated condition, while in other cases the radials 
still remain in connection with it, and form a perfectly symmetrical whole, no one of 
them preponderating in size over the others. They have only been seen in Cotylecrinus 
docens, in which they were first figured by Deslongschamps. 
As in Holopus and in Steenstrup’s Cyathidium, they correspond to the sides 
of the pentagon, and the dorsal fossa is greatly reduced. With regard to the so-called 
centro-dorsal of Cotylecrinus, I am decidedly of opinion that the upper portion on which 
the radials rest represents the basals. The absence of sutures noted by de Loriol is no 
proof to the contrary, as we know from the condition of the Paleozoic Allagecrinus and 
Agassizocrinus, and of the recent Rhizocrinus and Bathycrinus.* This is in fact tacitly 
admitted by de Loriol himself in the suggestion that the whole of the calyx tube in 
Holopus and Cyathidiwm consists of anchylosed basals.° 
If then the so-called cupule of Cotylecrinus, instead of being a centro-dorsal as its 
1 Loe. ctt., p. 53. 2 Neues Jahrbuch fiir Mineralogie, 1857, p. 817. 
$ Mémoire sur la Couche 4 Leptena, Bull. Soc. Linn. de Normandie, t. iii. p. 181, pl. v. figs. 5, 6. 
4 Op. cit., pp. 174, 179. 5 Loe cit., p. 53. 
5 Palexontologie, p. 386. 7 Paléont. Frane., loc. cit., p. 190. 
® See Ann. and Mag. Nat. Hist., 1883, ser. 5, vol. xi. p. 329. ® Paléont. Frang., loc. cit., p. 191. 
