ADDITIONS AND CORRECTIONS. 355 
or three forms, presents the gradation of types from the corals of the family Cyatho- 
phyllidese to the bryozoid forms. 
NOTE C. 
CRINOIDEiE. 
Thysanocrinus. It may be uncertain whether the portions of crinoids referred to this 
genus on Plate xlii, figs. 2, 3 & 4, really belong to it, or to some other genus. An op¬ 
portunity of examining some other specimens has suggested a doubt as to the propriety 
of this reference. 
In the genera Glyptaster and Lyriocrinus, I have detected the existence of tentacula 
attached to the plates of the arms. The same character probably exists in Dendrocrifus 
and Macrostylocrinus ; but up to this time, I have failed to discover it in Ichthyocrinus 
and Lecanocrinus. I have likewise ascertained the existence of tentacula in the Stepi&no- 
crinus, as shown on Plate xlviii. Since these appendages exist also in the cystideans, we 
may infer that they form a part of the organization in all Crinoideae. 
Genus Hemicystites, page 69. This genus is apparently identical with Agelacrinites 
of Vanuxem, the description and figure of which I had overlooked at the time this vo¬ 
lume was written. This name was given by Mr. Yanuxem to a fossil of the Hamilton 
group, to indicate the occurrence of several in connexion or proximity to each other; a 
circumstance, however, which will not be found constant, or of generic importance. 
[ Paleontology — Vol. ii.] 
46 
