and allied Brachiopod genera. 402 
views of Cryptonella eximia, from the Lower Helderberg group, 
the earliest species of the genus known to me. 
Figs. 8 and 9. Dorsal and ventral views of Cryptonella (generic illustrations).— 
Figs. 10 and 11. Dorsal and profile views of C. eximia. 
The genus Cryptonella may be characterized as follows: 
Genus CryproneLta Hall, 1861.—Shells terebratuliform, 
equilateral, inequivalve, elongate or transverse, ovoid or sublen- 
ticular in form, without median fold or sinus, or with these fea- 
tures very slightly developed towards the base of the shell. 
Ventral valve with the beak extended or incurved, and termin- 
ated by a circular foramen which is limited on the lower side 
muscular and vascular a aon below the rostral cavity. 
In the dorsal valve, the 
of the crura, support a slender loop, the two 
_ Median line, extending into the cavity of the 
ventral valve, as shown in fig 
ve v n in figure 2, which, 
while looking upon the dorsal side of the loop, may sometimes 
