72 " CANADIAN FOSSILS. 



highest, those at the angles bemg the lowest ; but in F. tenuiradiatus 

 it is the very reverse : the angles of the plate are more elevated than 

 the centres of the sides. 



I dedicate this species to E. C. Chapman, Esq., Professor of 

 geology and mineralogy, in University College, Toronto. 



Locality and Formation. — Lot 26, Front Concession of Clarence, 

 Ch izy. 



Collector. — J. Richardson. 



XIX. Ateleocystites Huxleyi, Billings. 



Description. — The extraordinary little fossil, for which the above 

 name is proposed, is no doubt a Cystidean ; but of a group somewhat 

 widely separated from the ordinaiy types. There are several speci- 

 mens in the collection, but they all are half imbedded in stone, and 

 with one exception exhibit only the dorsal side. The form is sub- 

 quadrate, rounded at the apex and nearly straiglit at the base. The 

 dorsal side appears to have been quite flat when perfect, as the plates 

 which constitute the edges are bent forward towards the ventral 

 aspect at more than a right angle, so that the sides instead of being- 

 rounded presented a rather sharp edge. The ventral side was pro- 

 bably convex. 



The plates of the dorsal side are arranged in four series. The 

 basal series consists of four oblong plates, each of which is about 

 twice as high as wide. These four constitute rather less than the 

 lower half of the body. 



In the second series there are three plates, the central one being 

 broader than either of the other two ; it rests upon the upper edges 

 of the two plates which form the central pair of the basal series, and 

 is about equal to them in width. The right side of this plate is 

 longer than the left, owing to the truncation of the upper left hand 

 angle. These three sides occupy a little more than one-fourth of the 

 length of the dorsal side. 



The third series consists of an irregular row of four or five small 

 plates. There are two at the sides, and apparently three others 

 resting on the large central plate of the second series. Of these 

 however only two are distinctly visible, one in the centre and the 

 other on the left sloping upper side of the plate below. 



The fourth series is composed of a row of three or four small plates, 

 forming the margin of the cup on the dorsal side. Above these and 

 imbedded in the matrix are several small points which are suggestive 

 of the marginal ambulacral ossicula of the ordinary Cystidese. 



