SPIRIFERIDA. 323 
CHARIONELLA, Billings, 1861. 
Syn.—Cryptonella, Hall, 1861. 
Disir.—15 sp. Devonian; America, Spain. C. scitula, Hall. 
Shell resembling Athyris, but more elongate-ovate or approach- 
ing to Terebratula in form. Internal spires as in Athyris and 
Merista, but the dorsal hinge-plate is either obsolete along the 
middle, or anchylosed to the bottom of the valve. Foramen 
terminal, bounded on the lower side by one or two deltidial 
pieces, or by a portion of the shell. The mesial septum in the 
dorsal valve is either absent or rudimentary. 
Nucrieospira, Hall, 1859. 
Htym.— Nucleus, and spira. 
Distr.—7T sp. Silurian, Devonian; United States, England. 
N. ventricosa, Hall (exxxviii, 16-18). 
Shell punctate; spheroidal; beaked; hinge-line shorter than 
the width of the shell; cardinal extremities rounded. Internal 
Spires as in Spirifera. Ventral valve with a flattened space or 
false area beneath the beak, on each side of which, at the base, 
is a strong tooth; a narrow medio-longitudinal septum extends 
from the beak to the base. Dorsal valve furnished with a strong 
spatulate cardinal process, which, rising vertically from the 
cardinal margin, is closely grasped at its base by the cardin»l 
teeth of the other valve; and thence bending abruptly upwards, 
and expanding,is projected into the cavity of the opposite beak, 
lying close upon the under side of the false area. Cardinal 
process grooved to allow of the passage of the peduncie, for the 
protrusion of which a minute foramen is sometimes observed in 
the beak. ‘The crural processes originate at the base of the 
cardinal process. A medio-longitudinal septum as in the ventral 
valve. 
Surface of shell apparently smooth, under a lens punctate ; 
when perfect, covered with minute hair-like spines. 
The larger species of this genus present some analogy in 
external appearance with Spirigera, and the presence of internal 
spires increases the similarity. The cardinal teeth resemble 
those of Spirigera and Merista. In form, and in the punctated 
test, it simulates Magas; while the elongate cardinal process of 
the dorsal valve resembles that structure in Thecidium. 
Merisra, Suess, 1851. 
Syn.—Camarium, Hall, 1859. 
Distr.—Silurian—Devonian; Europe, N. Am. J. herculea, 
Desl. (exxxviii, 19). 
Shell impunctate, dental plates and dorsal septum supported 
by arched plates (“ shoe-lifter”’ processes, of King) which readily 
