REPORT ON THE CRINOIDEA. 195 
and the Cystids had no such arms, and the Holopodide and Hdriocrinus were stemless. 
None of the typical Pelmatozoa, however, are devoid of both stem and arms, with one 
or both of which the chambered organ seems to be correlated. A so-called pedunculate 
Starfish has already been described by Prof. Perrier,’ and it was with much disappoint- 
ment that I learnt from Mr. Sladen’ that Caulaster is far from being the interesting type 
which it was at first supposed to be. Iam not without hopes, however, that future 
morphological work upon Urchins and Starfishes may throw more light upon this question ; 
and there is very much to be done by those who will go into the study of the Paleozoic 
Starfishes equipped with a knowledge of the morphology of recent Echinoderms, and 
will not be content with merely compiling empirical descriptions of new species. 
Miiller’s original classification of the true or brachiate Crinoids divided them into 
three groups, Articulata, Tessellata, and Costata, the last including the problematical 
genus Saccosoma, which may perhaps eventually turn out to be an Ophiurid. Reference 
has already been made (ante, pp. 145-147) to the unsuitability of the Miillerian names 
Articulata and Tessellata for the two other principal divisions of the brachiate Crinoids. 
The latter is practically co-extensive with the Paleocrinoidea of Messrs. Wachsmuth and 
Springer.’ These authors have gone further than Zittel and de Loriol, and have pro- 
posed to divide up the Crinoidea (understood in the widest sense) into the following 
orders :—(1) Blastoidea; (2) Cystoidea; (3) Paleeocrinoidea; (4) Stomatocrinoidea ; 
(5 2) Costata. This classification, however, has been by no means generally accepted. 
Different as are many of the Paleocrinoids, e.g., Hucalyptocrinus, from a Pentacrinite, 
others, such as the Ichthyocrinidz, have many of the characters of a recent Crinoid ; and 
an arrangement which elevates the difference between Pentacrinus and Ichthyocrinus to 
the same importance as those between Pentacrinus, Pentremites, and Echinospherites 
respectively, appears to me to be founded on a misconception of the value of morpho- 
logical characters. 
On the other hand, although the definition of the Paleeocrinoidea which has been given 
by Wachsmuth and Springer is capable of improvement in one or two respects, it is far 
more correct and is based upon sounder morphological principles than any definitions of 
the Tessellata which have been drawn up by Miiller and his followers. But I cannot 
regard the two groups Paleocrinoidea and Stomatocrinoidea (Articulata or Neocrinoidea) 
as equivalent to the Blastoids and Cystids ; so that while keeping the Paleeocrinoids at the 
level of an order, I should rank the Blastoidea and Cystidea as classes, in accordance 
with the practice generally adopted in this country. 
Prof. Chapman* has proposed a classification of the brachiate Crinoids which “is 
1 Sur une Astérie des grandes profondeurs de l’Atlantique, pourvue d’un pédoncule dorsal, Comptes rendus, 
t. xcv. pp. 1879-1381. 
2 The Asteroidea of H.M.S. Challenger Expedition, part ii., Jowrn. Linn. Soc. Lond. (Zool.), vol. xvii. p. 217. 
3 Revision, part ii. p. 3. 
4 A Classification of Crinoids, Trans. Roy. Soc. Canada, vol. i., 1888. Section iv., 1882, pp. 113-116. 
