284 SMITHSONIAN INSTITUTION 



Ichthyocrinus phillipsianus n. sp. 



Plate XXXVI, figs. 13-14 



A large species. Crown ovoid, with rounded base curving from the column, 

 expanding rapidly; spread of calyx from RR to IIBn, 1 to 3.2; height to width 

 at that level, about 1 to 1.6; widest at the lower IVBr. Side outline convex, 

 cross-section at IIBr decagonal ; radial ridges prominent from RR up, rounded 

 below and becoming angular upward, extending the full length of the crown. 

 Surface smooth ; plates strongly imbricated. Maximum crown, 41 mm. high by 

 33 mm. wide at IVBr; width of column facet, 5 mm. 



IBB very small. BB small, covered by the column, and only visible in side 

 view, if at all, as small points. Brachials longitudinally elevated into median 

 ridges. IIBr 4; IIIBr 5 to 7 or 8, with two more bifurcations visible before 

 infolding; height to width of brachials above IBr, about 1 to 3. Arms diminish- 

 ing rapidly after third bifurcation and becoming very slender. Column un- 

 known beyond the proximal columnals, which are as wide as the base of the 

 calyx. 



Among some specimens obtained from Dudley, England, some years ago, labeled 

 Ichthyocrinus pyriformis, was one which always seemed to be out of place among the others ; 

 and upon the final close definition of the several species it appears that this specimen does 

 not agree with any hitherto described. I have since obtained three fragments of the same 

 form, and have seen in an English collection another specimen somewhat larger than mine. 

 With this confirmatory evidence I propose a new species, dedicated to the memory of John 

 Phillips, the author of the earliest species of the genus. 



This species is of the general type of /. corbis in its ovoid figure, smooth surface and 

 small basals, with the surface angularity of /. subangularis produced by the prominent radial 

 ridges extending from the radials to the end of the visible rays. The infrabasals are not 

 wholly resorbed as in /. gotlandicus, but they are very small. Part of the radials rest upon 

 the stem, and the whole of the radianal is concealed by it ; only the merest points of the 

 basals, if any, appear at the exterior. On the principal specimen the short fragment of the 

 stem was broken across very close to the calyx, and I ground off the thin adhering part of 

 the upper ossicle so as to clearly show the plates of the base. Thus views are obtained with 

 and without the stem attached (PL XXXVI, figs. 13a, b). 



From another specimen preserving the upper part of the rays we obtain interesting 

 details of the so-called imbricated structure of the plates, and of the extreme proportionate 

 depth of the higher brachials (figs. i^a-e). The imbrication of the plates is very pronounced, 

 and the transverse elevations show distinctly in a dorsal view ; they are higher, broader, and 

 in every way more conspicuous than in any other species. 



This species wholly lacks the characteristic pear-shaped figure of /. pyriformis, and its 

 ovoid contour, smooth surface, and small basals further essentially distinguish it from that 

 species. 



Types. In the author's collection. 



Horizon and locality. Silurian, Wenlock Group ; Dudley, England. The species has not 

 been recognized in Gotland or America. 



