The E'ew Species of Brachiopoda, 335 



septum extends forward from the apex. External surface cov- 

 ered with low, crowded and rather faint concentric lines. On 

 the interior, the surface bears a series of distant, deep but nar- 

 row radiating furrows, about twenty-five in number ; these do 

 not reach the apex, and increase in number toward the margin. 

 Between them are very fine radiating lines. The animal was 

 parasitic in its habit, attachment being considerably aided by the 

 overlapping margin of the upper valve. Length and width of 

 an average adult ; upper valve, 9 mm., lower valve, T.5 mm. 

 Lower Helderberg group. Near Clarlcsville, JV. Y. 



Crania agaricina. 



Plate 3, fig. 10. 

 Crania agaricina, Hall. Palaeontology of N. Y., vol. VIII, pt. 1, p. 180, pi, 

 iv h, fig. 2. 1892. 



Shell small. Apex posterior, slighly elevated. Surface 

 covered by a few coarse, elevated, radiating lines, of which 

 about twelve reach the apex. These increase by intercalation 

 toward the margin to about thirty. The edges of these ridges 

 appear to be minutely granulose. Length of the original speci- 

 men (allowing for its incurvature upon the surface of attach- 

 ment), 6 mm. 



Lower Helderberg group. Near ClarTcsville^ N. Y. 



Crania pulchella. 



Plate 3, fig. 14. 



Crania pulchella, Hall. Palaeontology of N. Y., vol. VIII, pt. 1, p. 180, pi, 

 iv h, fig. 3. 1892. 



Shell like that of C. agaricina, but larger and with much 

 finer, more numerous radiating ribs. These are about sixty in 

 number at the margin of the valve. Length of the original 

 specimen, 8 mm. 



Lower Helderberg group. Near Olarksville, N. Y. 



Crania granosa. 



Plate 3, figs. 11, 12. 



Crania granosa, Hall. Palaeontology of N. Y., vol. VIII, pt. 1, p. 180, pi. ivh, 

 figs. 19, 20. 1892. 



The original specimen is an upper valve, quite irregular in its 

 growth, with a nearly central beak and strong convexity. The 



