612 Forty-fifth Report on the State Museum. 



Muscular impressions small, quadruple, not dendritic, the interior 

 pair being sharply raised. The brachial ridges originate from 

 between the adductor scars, curving gently outward, recurving, 

 at first gradually and then abruptly, to their anterior limit ; 

 thence turning suddenly backward, and again horizontally 

 inward, meeting the median septum near its anterior extremity. 

 Surface of the pedicle-valve covered with spines, which near 

 the beak are often curved backward, embracing some external 

 object. In some species all the spines of the valve have 

 evidently been at least of accessory importance in effecting 



Fig. 279. — Daviesiella Llangollensis. (Davidson.) 



attachment of the shell. The surface of the brachial valve may 

 be either spinous, lamellose or smooth. 



Type, Strophalosia Goldfussi, Mimster. 



Distribution. Middle Devonian-Permian. 



Daviesiella, Waagen. 1884. 



Shells large, with cardinal area and teeth well developed. 

 External surface covered with fine radiating striae and devoid of 

 spines. 



Type, Dwiesiella Llangollensis, Davidson (sp). 



Distribution. Coal measures. 



164 



