REPORT ON THE CRINOIDEA. 153 
notions of morphology. I freely admit the functional analogy of the under-basals of 
Encrinus, Erisocrinus, &c., with the central plate of Cupressocrinus or Stemmatocrinus ; 
but until the apparently simple nature of the latter shall have been proved to be really 
due to the disappearance of sutures, as in the basal ring of Bathycrinus, Rhizocrinus, and 
Agassizocrinus, I think that we must regard it as a top stem-joint, corresponding to what 
de Loriol calls the “article basal” in Apiocrinus and Millericrinus. 
Encrinus is remarkable as being the only Neocrinoid with ten (or twenty) arms of 
biserial joints, which increases its resemblance to Stemmatocrinus. There are, however, 
some species (Hnerinus gracilis) with ten uniserial arms, as in the other Neocrinoids and 
in Erisocrinus so far as yet known. This is also the case in. de Koninck’s genus 
Philocrinus from the Carboniferous strata of the Punjaub.*| But the basals seem to be 
much higher and the cup generally deeper than in either Hrisocrinus or Stemmatocrinus. 
The structure of the lower part of the cup was unfortunately obscured in de Koninck’s 
specimen, so that the presence of under-basals is still doubtful. 
Wachsmuth and Springer point out that the absence of any anal plates in Hrisocrinus 
and Stemmatocrinus, and the want of any knowledge of their ventral side render it 
doubtful “ whether they belong to the Cyathocrinide, or even to the Paleeocrinoidea ; and 
if it had not been for their marked resemblance to Hupachyerinus, in which a ventral 
tube has been observed, and that both were representatives of the same geological age, 
living under the very same conditions, we should have felt strongly disposed to place the 
whole genus with Hnerinus, with which it has, indeed, both in body and arms, the 
closest affinities.”” They think the number of radials to be not of material, or, at most, 
“only of generic importance ; but in Encrinus the aboral side of the body, or the plates 
which in all Cyathocrinide constitute the calyx, form almost a flat disk—at least do 
not extend beyond the basal plane—and this is the only distinction which can be 
discovered between the two forms in the fossil state. This, however, may involve 
important structural modification in the internal anatomy of the animal, and probably 
shut out Encrinus entirely from the Paleeocrinoidea.” 
Our knowledge of the anatomy of recent Crinoids, however, does not favour this 
supposition. There is very much less difference between the calices of Hnerinus and 
Erisocrinus than between that of Antedon eschrichti with high radials and a narrow but 
deep central funnel, and the low flattened calyx of any Actinometra. But the only 
difference exhibited by the ventral sides of these two types is that the mouth is central 
in the Antedon and excentric in Actinometra. I can therefore see no reason for 
supposing that Hrisocrinus had a solid inflexible vault built wp of the so-called oral plates, 
like that of the Cyathocrinidee, with which family it, as well as Stemmatocrinus, is placed 
1 Description of some Fossils from India, discovered by Dr. A. Fleming of Edinburgh, Quart. Journ. Geol. Soc., 
vol. xix. p. 4, pl. ii. fig. 5. 
2 Revision, part i. p. 142. 
(ZOOL, CHALL. EXP,—PART XxXxiI.——1884.) Ti 20 
