320 Mr. Sowerby on two new Species of Orhicula. 



verse and deep grooves, which are close set, being about half 

 their length distant from each other. I cannot ascertain whether 

 there is any natural opening in the center or not. The whole is 

 changed into crystalline Carbonate of Lime coloured by iron 

 rust; and it lies upon a mass of Limestone containing remains of 

 Encrini and Madreporites ; a single spiral univalve is also to be 

 observed. From the falls of the ChaudierCy on the Ottawa River 

 in Lower Canada. 



Reference to the Plate. 

 Pi. XL 



Fig. 1. Caryocrinites ornatus. b. the pelvic plates; c. the costal 

 plates. 



2. Pentremites florealis. a. natural size; b. pelvic or costal 



plates ; c. the scapular plates ; d. the interscapular plates ; 

 e. the ambulacrae ; /. the five terminal apertures surround- 

 ing the mouth ; g-. pelvis. . 



3. Pentremites Derbiensis. a. natural size; b. pelvic or costal 



plates ; c. the scapular plates ; d. the interscapular plates ; 

 e. the ambulacrae ; /. the five terminal apertures surround- 

 ing the mouth. 



4. Pentremites elliptica. a. natural size; b. pelvic or costal 



plates ; c. the scapular plates ; d. the interscapular plates ; 

 €. the ambulacrae ; /. the five terminal apertures surround- 

 ing the mouth. 



5. Fossil animal belonging to the family of Asteriadee from 



Canada. 



Art. XXXVIIL Descriptions of two new species of the 

 Genus Orbjcul^. Bt/ G. B. Sowerby, F.L.S. Sfc. 



Dr. Bigsby's researches in Canada have, among other novel- 

 ties, produced one of the two new species of this singular genus 

 here, described, and the other has been found without any locality 

 among the stores so long preserved by Mr. G. Humphrey. I have 



