Mr. J. E. Gray on the Arrangement of the Brachiopoda. 435 



XLV. — On the Arrangement of the Brachiopoda. 

 By J. E. Gray, Esq., F.R.S. 



Cuvier established this class of Mollusca as an order when he 

 published the dissection of Lingida, and it has been almost uni- 

 versally adopted. 



Linnseus/Miiller, Pallas, Poli, Blainville, Owen, Philippi and 

 D'Orbigny have made us acquainted with the animals of the 

 other recent genera, and showed how they differ from one 

 another. 



Mr. M'Coy in his work on the Fossils of the Carboniferous 

 Limestone, Mr. King in the ' Annals of Natural History/ and 

 more lately M. D'Orbigny in a paper transmitted to the Aca- 

 demy of Sciences, and published in the ' Annales des Sciences 

 Naturelles/ have availed themselves of these materials and pro- 

 posed an arrangement of the genera of this class into families. 



Mr. M'Coy's paper illustrates both the fossil and recent ge- 

 nera, and was an important addition to our knowledge; Mr. 

 King's corrected some of the synonyma of the genera and added 

 some details; M. D'Orbigny's is clever and rapid, and he has 

 evidently availed himself of the labours of both the above-named 

 gentlemen and of Philippi, though, with his usual want of gene- 

 rosity, he has not mentioned their names in any part of his paper, 

 and has given new names to several of his genera, though many 

 of them have long been distinguished by preceding authors. 



Not considering the arrangement proposed by these authors 

 as quite satisfactory, I have ventured to suggest the following. 

 Some may be astonished at my proposing to place what they 

 have been in the habit of considering as species of the same 

 genus in different orders and families, but the number of spe- 

 cies and forms known appears to me to justify this proceeding. 

 Bronn in his late work gives a list of more than 950 fossil spe- 

 cies of this class, many of them having several named varieties. 



Synopsis of the Orders. 



A. The oral arms recurved and affixed to fixed appendages on 

 the disc of the ventral valve. Shell minutely and closely per- 

 forated. Ancylopoda. 



1. Ancylobrachia. The oral arms affixed to calcareous plates, 

 forming hoops attached to the hinge-margin of the ventral 

 valve, and prominent in its cavity. 



2. Cryptobrachia. The oral arms sunk into grooves in the 

 convex centre of the inner surface of the ventral valve. 



B. The oral arms regularly spirally twisted when at rest. He- 



LICTOPODA. 



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