»«80 PALEONTOLOGY OF NEW-YORK. 



elevated septum running to the base of the shell. Muscular imprints 

 confined to a narrow oval space. 

 Surface apparently smooth : shell structure punctate, and, when perfect, 

 covered with minute hair-like spines. 



The larger species of this genus present some analogy in external appearance with 

 fyirigera, and the presence of internal spires increases the similarity. The cardinal 

 teeth resemble those of Spirigera and Merista : the punctate shell and the structure 

 of the hinge are, however, quite different. In form, and in the punctate character, 

 it simulates Magas; while the elongate cardinal process of the dorsal valve resembles 

 that organ in Thecidium. The genus, however, when regarded in all its features, is 

 very distinct from any of these; and the species will constitute, so far as regards 

 American palaeozoic brachiopoda at present known, a well-marked, beautiful, and 

 interesting little group. The geological range at present known extends from the 

 Niagara, through the Lower Helderberg, to the Hamilton; though it is probable we 

 Shall find them in other strata. 



IVocleospira ventricosa ( n. s.). 



Plate XIV. Fio. 1 ; and Plate XXVIII B. Fia. 2-9. 



Shell globose : valves almost equally convex. Ventral valve having a 

 narrow sinus extending down the centre from beak to base : beak 

 projecting above the other, strongly incurved and pointed ( in many 

 specimens the beaks are nearly equal). Dorsal valve having a central 

 depressed line, which is less conspicuous than in the opposite valve : 

 false area very small, concave. 



Surface marked by concentric lines of growth ; and, when perfect, 

 covered with minute hair-like spines, which, when removed, leave a 

 pimctate surface. 



The interior of the dorsal valve shows a faintly defined muscular area, a longitu- 

 dinal septum, and prominent recurved cardinal process, with an accessory process 

 on each side for the attachment of the spires. The ventral valve shows a longitudinal 

 septum similar to that of the opposite valve, with a more or less strongly defined 

 muscular depression ; area, or false area, a concave triangular space, over which the 

 acute beak is arched. In well-preserved specimens, the beak appears to be minutely 



