TRICCELOCRINUS? 213 



Phillips 1 under the name of Actinocrinus triacontadactylus, Miller? 3 is not clear, 

 but neither of them corresponds with Miller's own figure of that species. 

 Phillips' fossil probably does not belong to a crinoid at all, but to Sphssrospongia, 

 and our specimen is so indistinct that its true nature is very doubtful. It is more 

 like a fossil figured by Sandberger, 3 but even that may not belong to a crinoid. 



2. Class.— BLASTOIDBA, Say, 1825. 4 



1. Grade.— EUBLASTOIDEA, Bather, 1899. 5 



1. Series. — Troostoblastida, Bather, 1899. 5 



1. Family. — Troostocuinidj:, Bather, 1899. 5 



1. Genus. — Tiuccelocrinus, Meek and Worthen, 1868. 6 



This genus is defined as having "the body broadest below, and the three 

 spaces corresponding to the flattened sides of the typical species of Troostocrinus 

 so profoundly and broadly excavated as to impart a very remarkable appearance 

 to the lower part of the fossil." Dr. Bather 7 observes : — " A feature of more 

 importance is the enclosure of the distal portion of the hydrospires within the 

 thickness of the radial plate ; this is probably due to the upward growth of the 

 floor of the sinus, as has taken place, independently and to a less extent, in 

 Pentremites ." He points out that the excavations correspond with the three 

 interbasal sutures. Troostocrinus is separated from Metablastus on account of its 

 anal deltoid plate being irregular and external, and its possession of an anal 

 spiracle. 



1. Triccelocrinus? Lket, Whidbome. 



1881. Pentremites, Whidbome. G-eol. Mag., dec. 2, vol. viii, p. 288. 

 1886. Troostocrinus or Metablastus, Etheridge and Carpenter. Brit. Mus. Catal. 



Blastoid., p. 130. 

 1886. Metablastus ? Etheridge and Carpenter. Ibid., p. 198. 

 1889. Triccelocrinus ? Leei, Whidbome Geol. Mag., dec. 3, vol. vi, p. 80. 



1 1841, Phillips, ' Pal. Foss.,' p. 31, pi. xvi, fig. 43. 



2 1821, Miller, 'Nat. Hist. Crinoid.,' p. 95, pi. xxxviii, fig. 6. 



3 1855, Sandberger, ' Verst. Rheiu. Nassau,' p. 384, figure. 



4 1825, Say, ' Journ. Acad. Nat. Sci. Philadelphia,' iv, p. 292. 



5 1899, Bather, " Phylogenetic Classif. Pelinatozoa," 'Rep. Brit. Assoc' for 1898, pp. 920, 921. 



6 1868, Meek and Worthen, 'Proc. Acad. Nat. Sci. Philadelphia' for 1868, p. 358. 



7 1900, Bather, 'Blastoidea' (in E. Ray Lankester, 'Treatise on Zoology'), III, p. 87. 



