NO. 2 BRACHIOPOD SUPERFAMILY STENOSCISMATACEA GRANT 99 



rounded, both fold and sulcus beginning far forward, normally more 

 than 5 mm. anterior to beaks ; costae entirely absent from flanks, nor- 

 mally absent from fold (slight hint of costation at extreme anterior of 

 one specimen) producing smooth margins; posterolateral edges of 

 brachial valve overlapping edges of pedicle valve nearly to widest part 

 of shell ; valves meeting at acute angle around anterior, produced in 

 some specimens to form narrow stolidium on crest of fold, narrowing 

 on sides of fold : none observed on flanks ; growth lines fine, closely 

 spaced; growth laminae slightly stronger, widely and irregularly 

 spaced. 



Pedicle valve swollen in umbonal region, flatly convex toward 

 flanks, slightly reflexed (concave) at flanks of some specimens, 

 strongly convex longitudinally through sulcus but without abrupt 

 change in convexity; beak thick, blunt (but with apex sharp), mod- 

 erately long, normally erect, but not curving tightly against brachial 

 beak ; beak ridges blunt, short ; delthyrium narrowly trigonal, sides 

 constricted by small, disjunct or barely conjunct deltidial plates, leav- 

 ing small, slotlike foramen, not penetrating apex of beak. 



Brachial valve more strongly convex; umbonal region swollen, 

 profile flat along crest of fold, sloping strongly toward sides; beak 

 blunt, apex within pedicle valve. 



Pedicle valve interior with dental plates forming deep spondylium, 

 sessile for about 1 mm. in apex of beak, elevated on median septum 

 duplex for remainder of length ; septum extending anteriorly slightly 

 less than half length of valve, spondylium about 1 mm. shorter than 

 septum. 



Brachial valve interior with camarophorium beginning in apex, 

 curving slightly ventrally on high median septum, septum extending 

 anteriorly along floor about one-third length of valve ; trough extend- 

 ing farther toward anterior, producing concave anterior edge to sep- 

 tum ; camarophorial trough shallow, rather broad near midlength ; 

 intercamarophorial plate extending from underside of hinge plate to 

 intersect camarophorium, extending anteriorly about half length of 

 camarophorium ; hinge plate in apex of valve, posterior part swollen 

 to form small, finely fimbriate cardinal process ; crura extending ante- 

 riorly from edge of hinge plate, following course of camarophorium, 

 reflecting its ventral curvature. 



Holotype.—XJSNM 142121, pi. 10, fig. 2d. 



Comparisons. — Coledium erugatum is characterized by its smooth 

 shell without costae on fold or flanks, its high and relatively narrow 

 fold in the anterior commissure, and by presence on some specimens 

 of a narrow stolidium projecting from the crest of the fold. A stolidium 

 is not preserved on the flanks of any specimens, but the valves meet in 



