NO. 2 BRACHIOPOD SUPERFAMILY STENOSCISMATACEA — GRANT 19 



Fig. 1. — Reconstruction of arrangement of principal muscles in Stenoscisma- 

 tacea based on Stenoscisma. 



A. Interior of pedicle valve and cutaway brachial valve showing seating of 

 paired proximal end of diductor within spondylium : c — camarophorium ; d — 

 diductor muscle ; s — spondylium. 



B. Interior of brachial valve showing areas of attachment of adductor mus- 

 cles : blackened area is paired anterior adductor, stippled area is paired poste- 

 rior adductor : c — camarophorium ; cp — cardinal process ; cr — crus ; hp — hinge 

 plate ; icp — intercamarophorial plate. 



C. Side view along midline, showing mechanical arrangement of muscles : 

 diductor muscle (d) extends from cardinal process to spondylium ; anterior ad- 

 ductor (aa) and posterior adductor (pa) muscles extend from midline of spon- 

 dylium to camarophorium. 



D. Reconstruction of muscles, enlarged and spread to show arrangement : 

 diductor (d) single at cardinal process, paired in spondylium; adductor single in 

 spondylium, dividing in camarophorium to form posterior adductors (pa) and 

 anterior adductors (aa), surfaces of attachment blackened or stippled corres- 

 ponding to pattern of attachment areas in figure B. 



