NO. 2 BRACHIOPOD SUPERFAMILY STENOSCISMATACEA GRANT I39 



than on fold, number greatly variable. Growth lines fine, closely 

 crowded ; growth laminae slightly stronger, irregularly spaced ; radial 

 striae absent. 



Pedicle valve flatly convex transversely, more strongly convex lon- 

 gitudinally through sulcus ; beak short to slightly prominent, blunt or 

 weakly attenuate, nearly straight or suberect to erect, with sharp 

 apex; beak ridges distinct or absent; delthyrium small, triangular, 

 normally constricted by small, triangular, conjunct or disjunct del- 

 tidial plates, leaving small, oval foramen ; posterolateral flanges broad, 

 elongate, normally covered by edge of brachial valve, marked by weak 

 growth lines. 



Brachial valve strongly convex transversely and longitudinally, 

 umbonal region normally somewhat swollen; beak blunt to slightly 

 attenuate, apex within pedicle valve, covered by pedicle beak or del- 

 tidial plates. 



Pedicle valve interior with small blunt hinge teeth elongate parallel 

 to sides of valve; dental plates nearly parallel where connected to 

 hinge teeth, converging near floor of valve to form deep, scoop-shaped 

 spondylium, joined along median line to form low supporting septum 

 increasing in height slightly toward anterior, extending forward some- 

 what less than one-third length of valve. Muscle marks in spondylium, 

 weak and poorly differentiated, bounded at posterior by light trans- 

 verse line or ridge dividing off posterior third of spondylium ; pallial 

 trunks diverging from anterior end of median septum, each bifurcating 

 repeatedly toward margins, producing numerous short branches at 

 margins, extending to proximal edge of stolidium, there each splitting 

 into several branches radiating across stolidium. Transverse gonocoel 

 troughs originating near anterior of median septum (fig. 2) . 



Brachial valve interior with subtrigonal hinge plate striated or 

 thickened at apex to form cardinal attachment for diductor muscles; 

 hinge sockets short, narrow, finely denticulate, located at lateral ex- 

 tremes of hinge plate ; crural bases diverging narrowly from anterior 

 of cardinal knob, filled between and laterally to form hinge plate, be- 

 coming free anteriorly, extending forward as slender crura, outwardly 

 bowed and ventrally curved, ends nearly touching anterior edges of 

 ventral spondylium in closed shells. Median septum thin, high, height 

 increasing anteriorly, anterior edge nearly perpendicular to floor of 

 valve, upper edge capped by spoon-shaped camarophorium with slight 

 elongation of anterior along median line ; posterior part of inner sur- 

 face of camarophorium braced to hinge plate by median intercamaro- 

 phorial plate. Muscle marks within camarophorium, anterior adduc- 

 tors elongate, narrow, median, extending out onto median lobe of 

 camarophorium ; posterior adductor marks lateral, somewhat broader, 



