1886.] NATURAL SCIENCES OF I'HILADELPHIA. 89 



is no trace of sutures between them ; but the sutures gradually 

 become more marked, and turn in the larger ones into rather 

 distinct grooves. No central plate has been observed as in 

 Haplocrinus, and nothing is known of the ventral surface in any 

 of the larger specimens. Column short, of vermiform appear- 

 ance ; composed of small, low, rounded joints, with a circular 

 central canal. 



Geological Position, etc. Restricted, so far as known, to the 

 top of the Carboniferous limestone of Scotland and America. 



1881. Allagecrinus Austin! Ether, and Carp. Type of the genus. Ann. and Mag., 



vol. vii, p. 289, Pts. 15 and 16. Upper Carboniferous limestone of Scotland. 



1882. A. Carpenteri Wachsm., Bull. I, State Mus. Nat. Hist., p. 40; also Geol. Rep. 



Illinois, vol. vii, p. 341, PI. 29, fig. 14. Kaskaskia group. Monroe Co., 111. 



Family XIV.-SYMBATHOCRINID^, W. and Sp. 



We refer to this family the genera : Symbathocrinus^ Phimo- 

 crinus, Stylocriniis, Stortingocrinus, Pisocrinus, Triacrinus and 

 Lageniocrinus. Zittel made of these genera two families ; he 

 placed Symbathocrinus, Phimocrinus and Lageniocrinus, to which 

 he added Cupressocrinus, under the ^^ Cupressocrinidae,^^ and 

 Pisocrinus, Triacrinus, with Catillocrinus, under the "Piso- 

 crinidae.^'' These groups were adopted by De Loriol and S. A. 

 Miller. We willingl}'- admit that Cupressocrinus agrees with 

 Symbathocrinus and Phimocrinus very closely in the mode of 

 articulation and in the arm structure ; but they differ essentially 

 in other points. Cupressocrinus has a large dorsal cup, basals and 

 underbasals, and three or four large peripheral canals, which fol- 

 low the column. Nothing of this has been found either in Sym- 

 bathocrinus or Phimocrinus, which both have a very small dorsal 

 cup, and a small central opening along the column. After sepa- 

 rating Cupressocrinus, and making Symbathocrinus the type of 

 the group, it is extremely difficult to establish family distinctions 

 between Symbathocrinus and Zittel's Pisocrinidae. Not even the 

 irregularity in the construction of the calyx will hold good, as 

 also in Symbathocrinus the symmetry is disturbed by the 

 presence of an anal plate. Gatillocrinus, which also had been 

 identified with these groups, has a ventral sac, and has been 

 referred by us to the Fistulata. 



7 



