62 The Ottawa Naturalist. [Aug.-Sept. 



the anal pyramid is large and distinct. It is situated a little 

 more than half way from the center to the margin, and is com- 

 posed of a ring of seven or eight long triangular plates. In some 

 specimens it is situated half way between rays I and V, while 

 in others it is eccentric, and nearer V than I, as in the type. 



The holotype is a large specimen, 15.5 mm. in diameter. 

 Other specimens on the same slab with it (all figured) are 11.5, 

 10, and 9 mm. respectively. 



This species differs from L. dicksoni in having shorter rays, 

 one or two of which are solar, and in having much smaller inter- 

 radial plates. It is most hke L. platys, but has more numerous 

 supra-oral plates. While small specimens of L. incondiuis have 

 straight, broad arms, they may readily be distinguished from L. 

 hillingsi or L. youngi by the more numerous supra-oral plates. 



Horizon and locality :^— This species is common in the 

 "Cystidbed" in the "Prasopora zone" on both the Ottawa and 

 Hull sides of the Ottawa River. It occurs at Peterboro also. 



The holotype is No. 1409 in the Geological Survey Museum 

 and was collected by Mr. T. C. Weston. It is undoubtedly from 

 the " Cystid zone " at Queen's Wharf, Ottawa, Ont. 



Explanation of Plate. 



1. LebetodiscMS inconditus Raymond. Four specimens 

 in natural position, resting on the sea bottom, showing that they 

 were not attached to shells or other objects. With the decay of 

 the animal the central portion sinks in, leaving an elevated ring 

 of marginal plates. The largest specimen is the holotype. x 1 .5. 



2. Lebetodiscus multibrachiatus Raymond. The holotype, 

 showing the branching arms. The specimen does not lend itself 

 readily to photography, x 3.8'. 



3. Lebetodiscus chapmani Raymond. The holotype. x 3. 



4. Lebetodiscus youngi Raymond. The holotype. x 3.8. 



5. Lebetodiscus platys Kd^ymond. The holotype. x 1.5. 



6. Lebetodiscus loriformis Raymond. The holotype, a 

 large part of the surface of which is concealed by shale, x 2.8. 



Figs. 1 and 5 were made at the Geological Survey photo- 

 graphic laboratories. Figs. 2, 3, 4, and 6 were made by Mr. 

 Nelson at the Museum of Comparative Zoology, through the 

 kindness of Director Samuel Henshaw. 



