231 



indented by the penultimate whorl. In the upper whorls there are four 

 concave spiral grooves or bands, separated by three angular carinse. The 

 lower sides of the whorls are covered with numerous sharp spiral carinae, 

 two or three in the width of one line. Umbilicus open, disclosing the 

 whorls to the apex. On one of the specimens there are indications of fine 

 transverse lines of growth. 



Width of the largest specimen at the aperture 16 lines ; height from 

 the lower side of the aperture to the apex 14 lines ; width of the aperture 

 7 lines. 



This species resembles a strongly carinated Cyclonema, and may be, 

 perhaps, a species of that genus. 



. Locality and Formation. G, Cape Norman, Newfoundland ; Quebec 

 group. 



Collector. J. Richardson. 



MUKCHISONIA CATHARINA. (N. sp.) 



Fig. 215. Fig. 216. 



Fig. 217. 



Fig. 218. Fig. 219. Fig. 220. 



Fig. 215. Murchisonia Catharina. 

 216. M. acrea. 

 2ll.M.Jldelina. 

 218. M. simulatrix 

 219. M. Cicelia. 

 220. M. sororcula. 



A variety of M. gracilis. 

 A variety of M. perangulata. 



Description. Shell small, slender ; whorls about fifteen, extremely 

 and sharply angular in the middle, the space between each two of the 

 caringe being deep and uniformly concave. The form of the spire is that 

 of a deeply threaded screw. The suture appears to be about half way 

 between the carinations in the bottom of the concave space. Apical 

 angle from 10 P to 15. Surface unknown. 



Length of a specimen with fourteen whorls, from the apex downwards, 

 10 lines ; width of the last whorl 3 lines. 



