﻿78 



BRITISH DEVONIAN BRACHIOPODA. 



blance to some variations in shape of the shell under description, and to which Linnaeus 

 applied the denomination of Anomia pecten {' Syst. Nat.,' 12th ed., p. 163, 1768); it is 

 the same shell as was subsequently published by Wahlenberg, Dalman, Hisinger, myself, 

 and others, under the same specific denomination, although some few authors have erro- 

 neously supposed that the Anomia pecten of Linnasus is specifically different from that 

 subsequently so named by Dalman, Hisinger, and others. 1 Our present purpose is simply 

 to notice the general resemblance of the Linnaean shell to some varieties of the Devonian 

 and Carboniferous Str. umbraculum and crenistria, and to mention that hitherto, with but 

 few exceptions, palaeontologists have considered the Silurian A. pecten to be specifically 

 distinct from the two species above recorded. 



While describing the Carboniferous Str. crenistria, we enumerated a certain number 

 of its synonyms, as well as of its variations in shape, and were able, I trust, to show that 

 this variable shell had passed insensibly through every variation connecting the concavo- 

 convex shapes with the bi-convex ones, and were also able to demonstrate how variable 

 was the striation in different examples of the same species. 



We will now consider the Devonian form which Prof. M'Coy states to be " distin- 

 guishable from 0. crenistria by the greater convexity of the entering (dorsal) valve, with 

 its slight mesial depression, also by the thicker, closer, and more equal striae, the narrow 

 spaces between which are either quite smooth or only marked by regular transverse lines 

 of growth totally different from the deep, minute, irregular wrinkles of the Carboniferous 

 species." 



The first figure of the Devonian shell with which I am acquainted was that published 

 by Hiipsch in 1711, but it was only in 1820 that the species received from Schlotheim 

 the denomination of umbraculum ; and therefore, should the Carboniferous and Devonian 

 forms prove identical, Schlotheim's name would hold priority over that proposed by 

 Phillips in 1836. Schlotheim considered his Terebratulites umbraculum to be distinct 

 from the Anomia pecten of Linnaeus, which also he describes at p. 255 of his 

 ' Petrefactenkunde.' 



In 1837 Baron von Buch figured and described Schlotheim's species under the deno- 

 mination of Orthis umbraculum, and mentioned Sp. crenistria as a synonym ; he also stated 



1 At p. 125 of Hanley's 'Ipsa Linnaei Couchylia' (18.35), Mr. Sharpe has stated, " The only specimen 

 in the Linnaean collection which at all answers to the description is the Strophome/in {Orthis) pecten (Dalman, 

 Vet. Act. Hand., 1827, pi. i, fig. G — Hising. Lethaea Suec, pi. xx, fig. 6) is still preserved in the box 

 so marked in the cabinet. Dalman's figures and description prove that the Swedisli naturalists 

 have kept up the knowledge of the species. The shell to which Sowerby has given the name of 

 Orthis pecten (Sil. Syst., p. 21, fig. 9) is very different, and may be readily distinguished by its finer and 

 more numerous striae and by its greater length. O. expansa of Sow. (Sil. Syst., pi. xx, fig. 4), appears to 

 be the cast of the same shell, and consequently may be retained for the Sowerbian shell." In p. 251, 

 fig. 3, of the 2nd ed. of Sir It. Murchison's ' Siluria,' a good figure of the true Anomia pecten of Linnaeus 

 may be seen. 



