Greger — Rare and Imperfectly Known BracMopods. 73 



description of the exterior of his shell would suggest a species 

 of Pa/raphorhynchus ; he says " * * * surface marked by 

 from sixteen to eighteen distinct somewhat rounded plications 

 on each valve, which mostly reach the beak with some distinct- 

 ness, but are occasionally increased both by implantation and 

 bifurcation ; they are traversed by fine radiating lines and 

 crossed by fine concentric lines of growth.'' 



Camarophoria arctirostrata (Swallow). Figs. 11, 12. 



Bhynchonella arctirostrata Swallow, 1863, Trans. Acad. Sci. St. L., Vol. II, 

 page 34. 



This species was described by Prof. Swallow from material 

 collected at Boonville, Mo., from the Keokuk limestone. The 

 original description reads as follows : " Shell triangular or 

 cuneate, valves nearly equal, costate, striate. Yentral valve 

 most convex towards the beak, which is long, pointed, and 

 strongly incurved. Dorsal valve most convex in front ; beak 

 small, pointed, and strongly incurved. Both valves flattened 

 in the middle, and bent abruptly near the margins, forming 

 perpendicular subrectangular faces on the sides and one more 

 or less convex and rounded on the front. Each valve marked 

 with from fourteen to sixteen rounded, radiating, plications, 

 which extend to the beak — two or three implanted — and are 

 ornamented by fine longitudinal striae, and by obsolete concen- 

 tric folds. The angle at the beak very variable." 



Our figures are from specimens collected at the type locality 

 and labeled by Prof. Swallow, being a part of the Boyce col- 

 lection. Average measurements are as follows : length, 15 mm ; 

 breadth, 15 mm ; thickness, 12 mm . 



The general outline of this species at once recalls Camaro- 

 phoria subcuneata Hall, which fact was noticed by Prof. Swal- 

 low, but the peculiar, interrupted, hair-like lines on the plications 

 at once removes the possibility of its belonging to Hall's 

 species. Prof. Swallow's statement that the ribs are orna- 

 mented by longitudinal striae is correct only in a sense, since 

 the striae are not only interrupted but are also inclined to 

 curve down to the interradial grooves. Sinus and fold obso- 

 lete or wanting in this species. 



Paraphorhy7ichus gibbosum sp. nov. Figs. 1-6. 



Bhynchonella sp. Keyes, 1894, Mo. Geol. Surv., Vol. V, pi. xli, figs. 8 a-b. 



Shell elongate-OA r ate, very gibbous, greatest width at or 

 anterior to the median line, fold and sinus obsolete or wanting 

 in most examples. Yalves ornamented with a few coarse ribs, 

 irregular in number and position, increased by implantation 



