60 The Ottawa Naturalist. [Aug. -Sept. 



the anterior pair between rays II and III, and III and IV, being 

 clearly seen, and the posterior one less distinctly. At the end 

 of each ray is a small, central terminal plate, suggesting the 

 ocular of a starfish. 



The greatest diameter is 24 mm. 



This species is quite like L. chapmani but differs from it in 

 its larger size, longer and more slender arms, less circtilar outline, 

 and the curvature of rays I and IV. 



Horizon and locahty: — The type and only known specimen 

 (No. 7941, Vict. Mem. Mus.) was collected at Ottawa by the 

 late T. C. Weston in 1881. It is presumed to be from the 

 "Cystid beds," probably from the foot of Parliament Hill or 

 Queen's Wharf. 



LeBETODISCUS MULTIBRACHIATUS SP. NOV. 



(Plate 1, fig. 2). 



This is a small Lebetodiscus, and remarkable for the pos- 

 session of eight rays, instead of the usual five. Rays I and V are 

 far apart and curve somewhat toward each other, thus partially 

 embracing the anal area. All the other rays are approximately 

 straight. Rays I, II and IV, are all bifurcated, I and II near the 

 center, while IV bifurcates half way between the center and the 

 margin. The disc is not symmetrical, ray III being crowded 

 to the right of its normal position, and rays I and II taking up 

 as much space as rays III, IV, and V. All the rays are short 

 and the border outside them is wide, with rather large imbricating 

 plates opposite the inter-ambulacral areas, and a margin of 

 small plates outside. The supra-oral plates are of the simple 

 type of L. billingsi, chapmani, yoitngi and pileus, No. 5 being a 

 large wide plate, and the two plates anterior to it small. The 

 inter-ambulacral areas are small, and are covered with small 

 plates. Unforttmately the anal area is not well preserved. The 

 type is 10 mm. in diameter. 



This form, since it has numerous arms, naturally suggests 

 the recently described Thresherodiscus ramosus Foerste, but is 

 really not allied to that species, which has three primary rays, 

 all of which bifurcate at least twice. The present species is 

 much more closely allied to L. chapmani and to L. billingsi, and 

 when first noted several years ago, was supposed to be an abnor- 

 mal specimen of one of these species. It is of interest to note that 

 this form is found at the same horizon, the "Crinoid layers" 

 (Hull or Curdsville forniation) in the lower part of the Trenton, 

 as Thresherodiscus ramosus, these being the oldest of the Age- 

 lacrinitidae. Unfortunately the specimens found at Kirkfield 

 are ustially very badly preserved, so that it is not known how 

 many of the specimens so far found are to be referred to this 



