318 Mr. Sowerby on a Fossil 



acutiusculo ; interscapulares mediocres, ad centrum superne 

 fere attlngentes; ambulacrce angusti, sublineares, superne 

 paululum expansi, sulcis longitudinalibus tribus, interstitiis 

 crenulatis. Long. ^^. lat. -^ unc. 



This species of Pentremites is elliptical, subtruncate at its 

 inferior extremity, where the ambulacrae terminate and form five 

 somewhat angular prominences; the pelvis is Tery small, penta- 

 gonal and rather concave ; scapulars very large reaching three- 

 fifths of the distance from the base towards the upper extremity, 

 broader at the upper part, the interscapular notch at the upper 

 edge having a rather acute angle : interscapulars of moderate 

 size, nearly reaching to the center above, quadrangular, the 

 upper angle being the more acute : ambulacrce narrow, nearly 

 linear, spreading a little at the upper end, forming three longi- 

 tudinal grooves, of which the interstices are crenulated. The 

 external surface of pelvis, scapulars and interscapulars is covered 

 in this as well as the last species with minute grains, which are 

 partly arranged in rows corresponding with the lines of growth. 



A few specimens of this singular production have been oblig- 

 ingly communicated to me by Mr. Joseph Kenyon of Preston, 

 Lancashire, near which place they are found. 



Art. XXXVII. Notice of a Fossil belonging to the Class 

 Radiaritty found hy Dr. Bigshy in Canada, By G. B. 

 Sowerby, Esq, F.L.S,, S^c, 



Among the numerous and highly interesting organic remains 

 discovered by the indefatigable Dr. Bigsby in Canada, the truly 

 singular and new one which he has obligingly permitted us to 

 describe in the present number, may perhaps, on account of its 

 belonging to a family so very rarely found in a fossil state, be 

 considered as one of the most interesting and valuable. 



Upon examination of this fossil we do not immediately recog- 

 nize its affinities, for it bears a near resemblance to the arms of 



