85 
rior end is slightly truncated; the other obtuse ; they 
are nearly equal in width, that is about one-sixth of the 
length. . 
I have seen this species from Felmarsham, in Bedford- 
shire, where it was collected by the Rev. T. O. Marsh,* 
and also from other parts of the Cornbrash Limestone 
stratum. 
* This gentleman’s name has been erroneously given at p. 70, for which 
I have to beg his pardon. 
