INVERTEBRATES. 



217 



Genus GILBERTSOCRINUS, Phillips. 



Si/non. — Ollacrinus, Cumberland, 1826. Appendix to Reliquiae Conservator (without 



generic or specific diagnosis or specific name.) 

 Gilbertsocrimis, Phillips, 183G. Geol. Yorkshire, part ii, p. 207. 

 Rhodocrinus (part), deKoninck and Lehon, 1854. Recherch. sur les Orinoides, 



p. 104; and of several other authors; (not Miller, 1821). 

 Goniasteroidocrimis, Lyon and Casseday, 1859. Am. Jour. Sci. Vol. xxviii, 



(2) p. 232. 

 Trematocrinus, Hall, 1860. Sup. Iowa Report, p. 70. 



Fig. 17. 



Fig. 18. 



Phillips's di- 

 agnosis of this 

 genus reads as 

 follows : 



"Basal joints 

 five, forming a 



Gilbcrtsocriiws 



bursa. 

 This cut shows 

 one of the rays with 

 the base of its 

 false arras, a, a, and 

 nearly under these 

 the true arm open- 



Gilbcrtsoerinus calcaratus, Phillips. 

 The above cuts are from Cumberland's Reliquiae 

 consercatce, where this species is figured under the 

 pentagon ', SLl- name of Ollaermus. Fig. «, side view, shows the 

 bases of false arms and the openings below for the 

 attachment of the true arms, which latter he wrongly 

 represented as if penetrating directly through the 

 plates instead of passing between them. Fig. 6 

 represents the vault with its opening, and the false 

 arm bases. Fig. c represents the under side, but 

 does not show the divisions of the base. 



prabasal [subra- 

 dials] five, hex- 

 agonal, forming 



a decagon, with five re-entering angles, from, 



which proceed five heptagonal first costals [first 



From °S radials], and five hexagonal second costals [sec- 



lips's Geol. Yorks, ii, i n • i -i -i • i i i Tj_i • l 



phiv. ond radialsj, bearing a pentagonal scapula |_third 



radial], supporting joints [secondary radials], which combine 

 into rounded arms, perforated in the centre. First intercos- 

 tals [first interradials] pentagonal. The following species have 

 been usually referred to Rhodocrinus, Miller, from which, it 

 appears to me, they differ entirely." 



He mentions but the following three species, viz : G. calcara- 

 tus, 4r. mammillaris and O. bursa, all from the Subcarboniferous. 

 His generic and specific descriptions are very brief and unsat- 

 isfactory, but his figures are tolerably good, and give a suffi- 

 ciently intelligible idea of the generic characters of the group. 



28 Sept. 5, 1866. 



