NO. 2 BRACHIOPOD SUPERFAMILY STENOSCISMATACEA — GRANT I3I 



mostly occupied by brachial beak; deltidial plates small, only slightly 

 restricting pedicle opening ; foramen not penetrating apex of beak. 



Brachial valve more strongly convex, greatest swelling also just 

 posterior to midlength, convexity increasing with length of specimen ; 

 beak short, rounded, apex within ped-'cle valve. 



Pedicle valve interior with dental plates converging to form large 

 boat-shaped spondylium, sessile in apex, then elevated on thin median 

 septum for remainder of length ; septum high for genus, attaining 

 height slightly above 1 mm. in large specimens, extending anteriorly 

 about one-fourth actual length of valve. 



Brachial valve interior with hinge plate in apex; camarophorium 

 beginning as small wings on sides of median septum, rather than as 



Table 28. — Measurements of Coledium therum from the Mississippian near 



Eureka, Nev. 



Measurements, in millimeters 



small ball or pair of swellings, separated from hinge plate by strong 

 intercamarophorial plate, camarophorium extending anteriorly about 

 half length of valve. 



Holotype.— USNM 14344 (Walcott, 1884, pi. 7, fig. 6-6c). 



Comparisons. — Coledium therum is characterized by its large maxi- 

 mum size, normally elongate subtrigonal to subpentagonal adults, late- 

 appearing costae that number two or three on fold and flanks of adults 

 but are absent from juveniles, and especially by its camarophorium 

 that is slender in cross-section at the extreme posterior (not a ball on 

 the top of the septum), and its incipient stolidium around the anterior 

 margins of a few specimens. It is larger than any other known species 

 of the genus except C. crassum (Hamlet) and C. dutroi n. sp., but its 

 median size is near that of the more bulbous and wider C. erugatum 

 n. sp. and C. torvum n. sp. It differs further from C. erugatum in its 

 costate fold and flanks; differs further from C. torvum in its fewer 



