194 Mr. F. A. Bather on British Fossil Crinoids: 



ray may be so branched no less than the others. It is to be 

 hoped that more specimens of this species may be found, so 

 that this question may be settled ; for it is very remarkable 

 that the same species should combine such regularity in the 

 })iniiules with irregularity in the arm-branching, 



Ihe anterior side of the Ventral Sac is partly exposed in 

 the proximal region, and is composed of small plates, which, 

 like the covering-plates, seem to run without distinction into 

 those of the Tegmen. ^Vhere the plates are disturbed, traces 

 of an articular facet can be distinguished on their upper sides, 

 corresponding to the ridge. (Fig. 2.) 



T/te Stem is pentagonal or slightly quinquelobate, the lobes 

 being interradial in position, while the radial sutures arc seen 

 to run down the depressions between them. The ossicles are 

 all ridged, but alternate in size. The width of the stem is 

 ^•2 millim. and the average height of the ossicles is "36 

 millim. (Fig. 1.) 



Compared with the stem of B. quinquehbus, that of the 

 present species is seen to be proportionally more slender and 

 less lobate. All the ossicles, instead of only alternate ones, 

 are ridged, while the ridges are more obvious in the depres- 

 sions and are of a finer appearance. 



The Horizon of the present specimen is more compatible 

 with its stage of development than that to which the type 

 specimen was, perhaps erroneously, assigned. 



EXPLANATION OF PLATE XL 



Botryocrinus quinquelobus, sp. n. 

 Fiy. L rt/435, Woodwardiau Museum, No. L Seen from anterior; with 



drawing of transverse section of the stem. Nat. size. 

 Fitj. 2. aA'io, AVoodwardiau Museum, No. 2. iSeeu from anterior. Nat. 

 size. 



Mastiyvcrinus loreus, gen. et sp. n. 



Fiy. S. «493, Woodwardian Museum. (Cyathocrinus arboretts, Salter, 



Cat.) Seen from rigl)t posterior interradius. Nat. size. 



All figures on this Plate are from drawings by Mr. E. "Wilson, Artist 

 to the Cambridge En»ravin": Co. 



XXXI. — British Fofisil Crinoids. — \' 1 1. ^lastigocrinus loreus, 

 710V. qen. et sp., Wenluck Limestone, Dudleij. Bv F. A. 

 Batheu, M.A., F.G.S. 



[Plate XL fig. 3, and IMate XIL] 



The turni described in this ]>aj)er appears to belong to the 

 family Doudrocrinidiv, series Dendrocriniti-s. It should 

 thercfoie have been considered before the Botryocrinites, 



