94 
Length 11.68 mm- (.46) ; breadth 21.6 mm. (.85); depth of 
both valves 11.22 mm. (44). 
Less mucronate, more ventricose, and with fewer plications 
than JS, subattenuata varicosa and bimesialis. Much more 
ventricose than S. bidorsalis. Apparently identical with an 
undescribed species from Columbus, Ohio. 
Spirifera filicosta. —Form and two-thirds the size of 8. 
Parryana Hall. Fold and sinus much less pronounced and, 
with the fewer plications, marked by numerous radial stria). 
Ventral beak much incurved ; area not well defined. 
Martinia athyroides. —Triangularly terebratuliform, with¬ 
out fold or sinus. Ventral valve nearly twice as deep as the 
other, with a projecting, somewhat incurved beak. 1STo true 
area, but a broad, triangular fissure extends to the apex of the 
beak. Shell-structure thin-lamellar—neither punctate nor 
fibrous. Incremental surface markings numerous, fine, regular. 
Length 14.22 mm. (.56); breadth 13.21 mm. (.52). Resembles 
Charionella Circe Billings, from Corniferous limestone, but 
the beak is not perforate. 
Spirigera eborea. —General appearance of small speci¬ 
mens of jS. concentricct , but more ventricose, with a fuller and 
more produced ventral beak. Shell substance extremely solid 
and ivory-like, but not punctate; surface polished, with nume¬ 
rous extremely delicate concentric striae. Length 9.4 mm. 
(.37); breadth 9.14 mm. (.36); depth of ventral valve 4.06 
mm. (.16). 
Merista lens. —Quadrate-rotund, lenticular, both valves 
equally convex, the ventral having the beak closely incurved 
over its opposite. Ventral sinus only represented by a slight 
anterior projection ; dorsal fold only a broad angulation of the 
valve, except anteriorly. Surface of casts marked by six nar¬ 
row, remote, radiating ridges around the middle of each valve, 
bifurcated nearer the margin, (vascular markings ?) Occlusor 
scars ligulate, deep. Shell thick, fibrous. Spires present. 
Length and breadth 19.81 mm. (.78). 
Trematospira ? liniuscula. —Form and size of 7\ perfo¬ 
rata Hall. Cast with numerous faint radiating lines. Ven¬ 
tral beak incurved, apparently imperforate. Dental lamellae 
two-fifths the length of the valve. Occlusor scars oval, deep. 
Dorsal valve with a transverse narrow area; false area of ven¬ 
tral valve with a triangular fissure extending to the beak. 
Fold and sinus reaching the beak, but very feeble. 
Pentamerus intralineatus. —Size of P. occidentals Hall, 
but broader and more regularly (though faintly) costate on the 
anterior two-thirds, with shallow ventral sinus reaching to 
beak. Shell-fibres arranged concentrically. Exterior with 
numerous wavy, sub-lamellose, concentric grooves, and fine 
intervening striae; interior with numerous fine, radiating, 
grooved striae. 
