BRACHIOPODA. 7 



coils are directed outward and upward toward the cardinal angles of the valves 

 and their variation in size and direction is in keeping with the differences in 

 the marginal outline of the shell. The number of revolutions of the ribbon 

 exceeds that in any other genus of brachiopods. There is no loop ; its position, 

 however, is indicated by a pair of short spinous processes originating on the 

 primary lamellae soon after their junction with the crura, and which are 

 directed inward with a slight convergence. 



The muscular area has about the same extent as that of the pedicle-valve, 

 though less distinctly impressed and generally more elongated. It is consti- 

 tuted of two pairs of adductor impressions with their surfaces radiately or pal- 

 mately striated. The anterior pair are central, narrow at their posterior ex- 

 tremities which are embraced by the broader posterior scars. 



A faint median septum is sometimes present. In some instances of import- 

 ance the socket walls are supported by septa which may be considerably pro- 

 duced over the bottom of the valve. 



In both valves the genital region is distinctly punctated, but vascular mark- 

 ings are rarely observed. 



Type, Anomites striatus, Martin (1809). Carboniferous limestone. 



Observations. — Historical. This most prolific genus received its designation 

 first in 1814, when its distinguished author, Mr. James Sowerbt, read a com- 

 munication before the Linnean Society entitled : " Some account of the spiral 

 tubes or ligaments in the genus Terebratula, Lam., as observed in several species 

 of fossil shells." The name was based upon the discovery of the spiral brachial 

 supports in the species Anomites striatus, Martin. This contribution was not 

 published until 1818 (Transactions of the Linnean Society, vol. xii, p. 514). 

 Meanwhile, in the second volume of the Mineral Conchology (p. 42, 1815), Sow- 

 ERBY published and described the genus, citing as the only example the Anomites 

 cuspidatus, Martin. Davidson has shown* that the author's intention was still 

 to regard A. striatus as the type, for appended to his paper in the Linnean 

 Society's Transactions is the remark : " I suspect A. cuspidatus figured since the 



* Introduction to British Fossil Brachiopoda, p. 81, foot note. 



