159 



Surface with fine obtusely-angular striae, six or seven in the width of one 

 line, making a sigmoid curve backwards until the bottom of the last whorl 

 is attained, when they turn a little forward and run into the umbilicus. 

 The latter is not seen in the specimen, but it must be small. 



Length 8 lines ; width 9 lines. 



Locality and Formation. Gait. In the Guelph formation; Middle 

 Silurian. 



Collector. J. Richardson. 



HOLOPEA GUELPHENSIS. (N. Sp.) 



Fig. 143. Holopea Guelphensis. 



Description. Shell turbinate ; apical angle about 80 ; whorls 3, 

 uniformly ventricose, the last one large ; aperture elliptical, its height 

 about one-fifth greater than its width ; umbilicus small, its width in the 

 cast being about one-fifth the width of the aperture. Surface unknown. 



Length about 1 inch ; width of last whorl, including the aperture, 9 

 lines. The two apical whorls occupy about one-sixth of the whole length. 



Locality and Formation. Gait. In the Guelph formation; Middle 

 Silurian. 



Collector. A. Murray. 



HOLOPEA GRACIA. (N. sp.) 



Description. Shell turbinate ; apical angle about 90 ; whorls four, 

 moderately and nearly uniformly ventricose, most prominent at about the 

 lower third ; suture not very deep. Length 13 lines ; width 12 lines. 

 The body whorl occupies about one half the whole length of the shell. 

 Umbilicus and surface unknown. 



This species very closely resembles H. G-uelphensis, but differs there- 

 from in having the body whorl proportionally not so large, while the most 

 convex part of all the whorls is in the lower one-third, instead of in the 

 middle. 



Locality and Formation. Gait. In the* Guelph formation ; Middle 

 Silurian. 



Collector. E. Billings. 



