88 AMERICAN JOURNAL 



A REVISION OF THE TEREBRATULID^ AND LINGULID^, 

 •WITH REMARKS ON AND DESCRIPTIONS OF SOME 

 RECENT FORMS. 



BY W. H. DALL, SMITHSONIAN INSTITUTION. 



In the preparation of this paper I have been much indebted to 

 the Smithsonian Institution, under the direction of Prof. Joseph 

 Henry, for the use of its collection of recent Brachiopoda, and 

 for the use of the cuts which illustrate the text of this article. 

 I am under great obligations to Mr. F. B. Meek, of the Smith- 

 sonian Institution, for assistance, especially in regard to the 

 fossil forms ; his knowledge of the latter being only equalled by 

 his kindness in imparting it. 



I am also indebted to Thos. Davidson, Esq., F.G.S., &c., for 

 much useful information and assistance, and for his unfailing 

 courtesy in correspondence. 



I have derived much assistance from the works of Messrs. 

 Suess, Deslongchamps, Hall, King and Davidson, and especially 

 from the admirable plates which accompany the excellent mono- 

 graphs of the last-named learned palaeontologist. 



The fact that I have departed from the arrangement hitherto 

 in general use, is due to the belief that the practice of combining 

 under one name forms differing in structure as well as detail, is 

 detrimental to the interests of science. With few exceptions, 

 the forms which I have separated sectionally, or generically, 

 have been accurately figured and described by other authors ; 

 yet, in order to refer to them specially, the student must make 

 a special study of all the forms, and search through paragraphs 

 and pages relating to other forms which have been united with 

 those of which he desires information ; a course which, though 

 popular from the greater latitude which it allows to the careless 

 and superficial observer, is yet reprehensible, as destructive of 

 the care and accuracy in detail which are so greatly needed in 

 the study of recent as well as fossil forms. 



The great interest which attaches to the theory of evolution 

 renders close discrimination all the more valuable at the present 



