74 Greger — Bare and Imperfectly Known Brachiopods. 



and bifurcation, entire surface covered with fine longitudinal 

 striae, valve margins sharply serrate. Pedicle valve inflated, 

 flattened in the middle, gently curved upwards in the anterior 

 and posterior regions with the posterio-lateral margins inflected, 

 beak somewhat prominent and pointed. Brachial valve 

 decidedly more gibbous than the former, beak less prominent 

 and obscured by that of the opposite valve, posterio-lateral 

 margins inflected or flattened, corresponding with the opposite 

 valve. 



This is one of the very rare brachiopods of the Burlington 

 limestone and well preserved specimens are seldom met with ; 

 it is only in specimens retaining the exterior uninjured that 

 the delicate longitudinal striae are to be observed. 



Our collection contains specimens from Louisiana, Mo., and 

 Hannibal, Mo., the last being the locality from which Dr. 

 Keyes obtained his specimens. Figures 1, 3, and 4 are of the 

 largest so far observed, measuring : length, 39 ram ; breadth, 25 mm ; 

 thickness, 28 mm . 



Paraphorhynchus ovatum sp. nov. Figs. 9-10. 



Shell elongate-ovate, greatest width anterior to the median 

 line, vertically compressed, the transverse diameter always 

 greater than the vertical, fold and sinus obscure, producing 

 only a slight sinuosity in the marginal line. Surface orna- 

 mented with eighteen to twenty low rounded ribs, which have 

 their origin near the beak, growing constantly larger as they 

 approach the front ; the surface is further ornamented by fine 

 longitudinal strige, three or four in the space of one milli- 

 meter. 



Pedicle valve but slightly inflated, sloping gently from the 

 center to the anterior and anterio-lateral margins and some- 

 what more abruptly to the posterior end ; posterio-lateral mar- 

 gins inflected, beak not prominent, incurved. Brachial valve 

 with less depth than the former, subequally sloping and 

 inflected in the posterio-lateral region ; beak small and blunt. 

 Average dimensions of the specimens in our collection : 35 mm 

 long, 27 mra broad and 16 mm in thickness, the greatest thickness 

 being in the umbonal region. 



Horizon and locality — Chouteau limestone, Kiesenger Bluff, 

 Warsaw, Benton County, Mo. 



