236 CARDINITD^. 



usually but slightly prominent, sometimes obsolete; lateral teeth 

 more or less deA-^eloped, often very thick ; muscular impressions 

 simple, deep. (Entirely fossil.) 



Carbonicola, M'Coy, 1855. 



JDistr.— 20 sp. Carboniferous ; Europe, United States. C. 

 acuta, Sowb. (cxxiv, 9*7). 



Shell elongated, solid, with moderately tumescent, not eroded, 

 beaks, somewhat impressed in front of them ; ligament strong, 

 external ; surface concentrically striated ; hinge with one very 

 thick cardinal tooth in the right valve, extending posteriori}^, 

 with one long anterior and one long posterior lateral tooth ; 

 muscular scars one either side, each surmounted by a small 

 accessory impression. 



Anthracosta, King, 1856. 



Etym. — Anthrax, carbon, in allusion to the carboniferous de- 

 posits in which the genus is usually found. 



Z)ist7'. — 61 sp. Devonian — Carboniferous ; Westphalia, Sax- 

 ony, Russia, Belgium, Great Britain, N. America. A. Lottneri, 

 Ludwig (cxxv, 10). 



Shell equivalve, inequilateral. Teeth one in each valve below 

 the umbone, rather low and massive; crown of tooth of right 

 valve excavated anteriorly and ridged posteriorly ; crown of 

 tooth of left valve ridged anteriorly and sloped posteriorly. 

 Umbonal ligamental fulcra each a furrow excavated in the hinge- 

 plate, between the umbone and tooth ; scars of the anterior set 

 of pedal muscles, situated above the anterior adductor muscular 

 impressions. 



Anthracosia differs from Unio, to which genus the majority of 

 the Unioniform shells have been referred, in its simpler dental 

 system and in the absence of supplementary pedal muscles. 



Anoplophora, Sandberger, 1862. 



Syn. — Unionites, Munst. Myacites, Auct. 



JDistr. — Triassic. A. lettica, Quenst. (cxxii, 37). 



Shell elongated, laterally moderately compressed , inequilateral, 

 beaks subanterior, hinge with a small indentation, without any 

 perceptible cardinal teeth and with very slightly thickened lateral 

 margins on either side ; anterior muscular impression cordiform, 

 enlarged, posterior very faint, ligament linear, external. 



Most of the species referable to this genus occur in the Trias ; 

 they difier from Cardinia by the want of hinge-teeth, and some 

 forms closely resemble Pleurophorus, but they appear to have a 

 thinner shell. 



