g8 The Ottawa Naturalist. [August 



Mr. Chapman presumably interpreted x, which he nowhere men- 

 tions, as a radial ; but the present identification, when once 

 made, is}[so obvious that only two facts need be adduced in 

 its support. First, the heptagonal outline of the plate here called 

 post.B. Second,the contrast between the conspicuous arm-facets on 

 1. post, and 1. ant. RR, and the absence of any such excavation on x. 

 Above x, in the angle between it and the proximal I Br. of r. post, 

 arm. are a few small plates (apparently not the ones alluded to 

 and figured as tegminal plates by Mr. Chapman), and one of these 

 seems to be folded at its edges as is so usual in the tube-plates of 

 this genus. The arm-facet, neither mentioned nor very exactly 

 drawn by Mr. Chapman, appears to have had straight, rather 

 steeply sloping sides, ending in a deep axial canal, which has 

 broken through to the front of the plate (compare the account of 

 the ventral groove and axial canal in B. crassus). It is not easy 

 to understand the true shape and proportions of the facet ; but the 

 narrowness of the primibrachs indicates that its width can scarce- 

 ly have been half that of the radial. 



AMERICAN SPECIES. 



Botryocrinus nucleus. 



Dendroctinus nucleus, Hall, 1876, Rep. N. V. State Mus. Nat. Hist. 



XXVIII, Documentary Edit., explan. pi. xv, ff. 7-9. 

 Cyathocrinus nucleus, Hall, 1879, op. cit., Museum Edit., p. 136. 

 Homocrinus nucleus, VVachsmuth & Springer, 1886, 'Revision of Palaeo- 



crinoidea',111, p. 220, Proc. Acad. Xat. Sci. Philadelphia, 1886, p. 144. 

 Botryocrinus nucleus, Bather, 1893, 'Crin. Gotland', Svensk. Vet.-Akad, 



Handl. XXV, No. 2, p. 104. 



Dorsal cup with straight sides up to the RR. which project 

 markedly towards the arm-facet. Slight trace of axial folding on 

 BB. Height of cup (8-1 1.5 mm.), 100 ; width at base, 43 ; width 

 at summit", 125-130. IBB low, much wider than high. BB wider 

 than high. RR higher than wide. Arm-facet more than .66 of 

 R. x supports 1 tube-plate. Proximal columnal circular, with 

 tendency to quinquelobation. 



Upper Wenlockian, Niagara shales of Waldron, Ind. 



Holotype, American Museum of Natural History^Jio... 1S98. 

 Plastotype in Briiish Museum, No. 14075. ^WO&At 



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