THE GEOLOGIST. 
OCTOBER, 1858. 
PAL^ONTOLOGICAL NOTES ON THE BRACHIOPODA. 
By Thomas DxVvidson, Esq., F.RS., Sec. G.S., &c. 
No. I. — Ori the Genera and Suh-gcnera of Brachiopoda that are pro- 
vided taith Spiral Appendar/es for the support of the Oral Arms, 
and Sp>ecics so constructed:, which have been discovered in British 
Carhoniferous Strata. 
Aui that pertains to tlie science of Palajontology is of consequence to 
the geological inquirer ; therefore a few notes and illustrations relative 
to the Brachiopoda may, perhaps, prove acceptable to the general reader, 
and, at the same time, stimulate some others to prosecute an inquiry 
upon which so much time and labour have been already expended. 
It was justly observed by a distinguished naturalist, that there exists 
a decided advantage in the same subject being investigated by a number 
of different observers ; and the truth of this statement has been fully 
substantiated by the information already acquired on all that concerns 
the affinities, classification, and anatomical structure of the Brachio- 
poda.* But it must also be remembered, that, although these topics 
may have been individually and collectively the subject of considerable 
*■ The larger proportion of naturalists have been in the habit of considering the 
Brachiopoda as constituting a separate class among the Mollusca, but anatomists 
have not hitherto agreed upon this important question. Mr. Hancock has en- 
deavoured to demonstrate the close structural conformity between the Brachiopoda 
and the Polyzoa, ivhile Dr. Gratiolct dissents from the Ticw taken by Professor 
Owen, who has placed the Brachiopoda between the Lamellibranchiata and the 
Tuuicata. 
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