No. 186.J 



43 



Surface marked by fine concentric strise; and partially exfoliated 



specimens show some obscure radiating strise. 

 Ventral valve flat or sinuate in the middle, and produced in a 



linguiform extension in front. 



From the similarity of structure, I liave presumed these forms to belong 

 to the same group as Spirigera and Merista ; but the presence of the 

 transverse septum seems incompatible with the existence of the internal 

 double spires. 



Under this genus I include Merista princeps and M. meeki ( Pal, N.Y. 

 Vol. iii, pp. 251 & 252, excluding figures 1-3, which may be regarded 

 as doubtful ). I have not yet been able to determine the internal structure 

 so far as to make satisfactory comparisons with similar parts of Camara- 

 phoria. 



The following generic illustrations are from Camarium typum of the 

 rocks of the Lower Helderberg group, associated with the Pentajnerus 

 galeatus and other well-known species. 



Fig. 1. Interior of a ventral valve, showing the arching septum. 



Fig. 2. A similar specimen where the septum is more extended down the sides of the 



shell : the upper part is somewhat broken. 

 Fig. 3. Longitudinal section of the ventral valve. 



r"^'^. 



Fig. 4. A cast from the interior of fig. 1. 

 Fig. 5. Dorsal view of a perfect specimen. 

 Fig. 6. Profile view of the same. 



