No. 1. — Report on the Brachiopoda obtained by the United 

 States Coast Survey Expedition, in Charge of L. F. de Pour- 

 tales, with a Revision of the Craniidye and Discinid.e by 

 W. H. Dall. 



(Communicated by Professor Benj. Peikce, Superintendent U. S. Coast 



Survey.) 



In the preparation of this paper I have been indebted to the Smith- 

 sonian Institution, under the direction of Professor Joseph Henry, for 

 the use of their library and collection of recent brachiopods ; to J. Gwyn 

 Jeffreys, Esq., F. R. S., for kindly lending specimens of the brachiopods 

 obtained by the English Deep-Sea Dredging Expedition, for comparison ; 

 and to Thomas Davidson, Esq., F. G. S., for many favors. 



The animals which compose this class are of peculiar interest to the 

 naturalist and geologist, as being represented in rocks of very early 

 ages, and continuously through the various formations up to the present 

 period. Their position in the natural system of classification being stil 1 

 a matter of discussion, all facts bearing on their anatomy and embryology 

 are of the highest interest. I have endeavored, therefore, instead of 

 compiling a mere list of species and descriptions, to enter as thoroughly 

 into the details of anatomy as the means at hand would allow, and have 

 considered the present a fit opportunity for rectifying the synonymy 

 of some groups which, from the confusion in which they have been 

 involved, have long been avoided by naturalists as stumbling-blocks. 



It is hardly necessary to add, that I am indebted for the opportunity 

 of doing this work to the kindness of Professor Agassiz, who placed 

 the materials in my hands for examination, with the kind concurrence 

 of M. de Pourtales and Dr. William Stimpson 



Class BRACHIOPODA Cuvier. 



Animals provided with two shelly valves, each of which, normally, is 

 bilaterally symmetrical. Valves united by three or more pairs of muscles, 

 which, with all the other soft parts (except occasionally the intestine) are 

 arranged in bilateral symmetry with relation to the longitudinal axis of 

 the valves, respectively. Organs consisting essentially of a mantle com- 

 VOL. III. 1 



