THE 
GEOLOGICAL MAGAZINE. 
NEW SERIES. DECADE II. VOL. IV. 
No. IV.— APRIL, 1877. 
OTIXG-XISTJ^Xj AETICLES. 
I. — What IS a Bkachiopod? 1 
By Thomas Davidson, F.R.S., F.G.S., Y.P.P.S., etc. 
PART I. 
(PLATES VII. and VIII. 2 ) 
W E are all aware that it is very often rauch easier to put a 
question than to obtain an entirely satisfactory ans wer, and 
I am consequently sorry to have to begin my few observations on a 
very extensive dass or group of organisms, by stating that zoologists 
and comparative anatomists have not yet entirely agreed as to the 
exact position it should occupy among invertebrate animals. 
The first species belonging to the dass were imperfectly and 
quaintly described and figured by Fabio Colunma as far back as 
1606, and for many years were supposed to be referable to the genus 
Anomia, one of the Lamellibranchiata ; but as was judiciously observed 
by Edward Forbes, “A close examination shows that there is no 
relationship between them, but only a resemblance through formal 
analogy.” It is during the present Century that the dass itself lias 
been worked out and understood, and this has been achieved after 
the most lengthened and persevering researches. 
It will not be possible in a short article to enter upon a complete 
history of the progress made by Science up to the present time with 
respect to the Brachiopoda. Suffice it to say, that many of the most 
eminent zoologists and palaeontologists have materially contributed 
to our knowledge of the group, and I have devoted the best portion 
of my life to its elucidation. We may however observe that, pre- 
viously to the present Century, several naturalists had published notes 
of some interest upon the Brachiopoda, which have helped to bring 
the subject under the special notice of the more experienced mala- 
cologists of our time. In 1675, 1687, and. 1688, Martini Lister 
published figures of a few recognizable species of Brachiopoda, and 
in particular of Productus giganteus. In 1696 Llhwyd proposed the 
name Terebratula for several of the Shells that had previously been 
referred to Anomia: he also gave some good figures of several 
1 This memoir is the substance of a lecture delivered by the author to the Brighton 
and Sussex Natural History Society on the l Ith of Febniary, 1875, and subsequently 
published in French with additions and plates in vol. x. of the Annales de la Societe 
Malacologique de Belgique for 1876. 
2 Plates IX. and X. will accompany Part II. 
DECADE n. — VOL. IV. — NO. IV. 
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