156 Scientific Intelligence. 
aboral side, led Professor Goette and Mr. Wachsmuth independ- 
ently to the conclusion that there exists a morphological resem- 
blance between them. This view has since been accepted by 
Dr. Carpenter, and he, as well as Wachsmuth and Springer, base 
thereon the different views which they respectively entertain con- 
cerning the summit plates of the Paleocrinoidea. 
The orals in most of the recent crinoids are confined to their 
larval state, but whether they are persistent through life, or are 
resorbed in the adult,the mouth and food grooves become ex- 
posed to view before the animal reaches maturity. In the Pale- 
ocrinoidea these organs are permanently closed by series of plates 
which collectively occupy the place of the orals in the Neocrinoid 
larva. The authors of the revision agree with Dr. Carpenter 
upon this point; but they differ from him as to which of the 
various summit plates in the Paleocrinoidea individually repre- 
sent the orals. 
The authors have ascertained that the summit and other vault 
plates, which were generally ignored by the earlier writers, have 
a high classificatory value. ‘They find them to be arranged upon 
a well-defined general plan which, to a considerable extent, 
should be regar ded as a counter part of that which is shown by 
the plates of the calyx. The plan consists of a central piece, 
which occupies the oral pole and covers the mouth, six proximal 
plates surrounding this central one, but they are not always in 
contact with it, and frequently radial dome plates, corresponding 
with the calyx radials. The authors conclude that the central 
piece of the dome, which they think primitively consisted of tive 
pieces, is the homologue of the basuls, and that it, represents 
morphologically the closed pyramid of five oral plates in the 
Neocrinoid larva, the proximals representing the calyx interra- 
dials. Contrary to this Dr. Carpenter believes that the orals are 
represented by the six proximals surrounding the central piece, 
the two smaller posterior ones being regarded by him as one 
plate divided by anal structures. -This view was formerly held 
by Wachsmuth and Springer, but they have since abandoned it. 
Dr. Carpenter regards the central piece as representing the 
dorso-central or terminal plate-of the column. Both parties 
support their opinion by extended arguments based on the latest 
researches upon both recent and fossil crinoids, with an earnest- 
ness which shows their full conviction of the correctness of their 
respective opinions. 
An important discovery is announced as to the relations of the 
parts on the dorsal side of the paleozoic crinoids which seems to 
be of much importance in their practical study ; and a statement 
of it will serve to illustrate the minute care with which these 
authors have prosecuted their work. They consider the first ring 
of plates below the radials as the true basals in all cases. In 
those crinoids which have a dicyclic base the lower ring of plates 
are called the underbasals. These are often very minute, con- 
cealed within the basal concavity, or hidden from external view 
