336 



the cup, there is a space where the pores have no definite arrangement, 

 but from this space they proceed up the sides in regular slightly undula- 

 ting rows. New rows are introduced at intervals according to the 

 increasing expansion of the cup. Most of the pores have a thin, sharp, 

 slightly elevated margin. The internal structure of the inner layer seems 

 to be reticulated, all the pores communicating with each other by longi- 

 tudinal and transverse canals of the same size as the external orifices of 

 the pores. 



Fig. 324. 



r 



Fig. 324. Calathium? pannosum. a, the internal surface ; &, side view of the specimen 

 showing the thickness of the inner poriferous layer. 



From what remains of it, it is clear that the cup of this individual must 

 have been at least 3 inches wide, and li in depth. But as the edges are 

 all broken, we cannot say how much larger it may have been when per- 

 fect. The rows of pores are on an average 1 line distant from each other, 

 and there are about 6 pores in 3 lines of the length of each row. 



The specimen is a silicified fragment, and was dissolved (by hydro- 

 chloric acid) out of one of the nodules of limestone, in which the species of 

 Brachiopoda figured on pp. 73, 75, 79,82, were found. That this species 

 is generically allied to Calathium will appear by reference to the follow- 

 ing, which will be described in this place for convenience of comparison. 



Locality and Formation. Point Levis ; in the upper part of limestone 

 No. 2, Quebec group. 



Collectors. Sir W. Logan, J. Richardson. 



