22 . F. A. BATHER, CR1N0IDEA OF GOTLAND. 



group II, and excluded all in the other groups. In 1886 Wachsmuth and Springer (Rev. 

 III, 165, Proc. j). 89) separated Symbathocrinus and other forms in III b froni vox Zittels 

 Cupressocrinidaa, and placed them in the same family as Pisocrinus; but instead of calling 

 tlic family »Pisocrinidae», as would have been natnral, they constituted a new faniily — 

 Symbathocrinidae. Vox Zittel's divisions, however, seem inore in accordance with the facts 

 tabulated above; a return therefore is here made to the Pisocrinidae, with this difference, — 

 Mycocrinus and Catillocrinus are separated as having no K', and form the family Catillo- 

 crinidae, W. and Sp. There is no reason why the Symbathocrinidae should not be main- 

 tained as a family including, probably, all the other forms referred to it by Wachsmuth 

 and Springer. 



The Family Pisocrinidae, as here understood, includes Pisocrinus, Triacrinus and 

 Calycanthocrinus. Consequently it cannot correspond with that of Angelin, which is main- 

 tained by Mr. S. A. Miller *), for both those authors base their primary divisions on the 

 number of basals; Triacrinus, for instance, would fall into the Synbathocrinidae of Mr. 

 Millek, which does not equal the Symbathocrinidae of Wachsmuth and Springer. IIow 

 utterly unphilosophical and absolutely untenable such an arrangement is, will be seen by 

 anyone that takes the trouble to read the description of Pisocrinus ollula. 



Pisocrinus. 



(Plate 1, figures 1—23.) 



1858. L. de Koxinck. Hull. Ac. Roy. Belg., 2 e ser., vol. IV, p. 104, Pl. II, and Geologiet, vol. I, 



pp. 182—184; London, May 1858. 

 1860. Synbathocrinns, C. F. RöMER, Silur. Fauna W. Tennessee, p. 55, Taf. IV, tig.-. 6 a, 6 l>\ Breelau. 

 1884. Triacrinus, E. N. S. RiNGUEimuo, Proc. Ac. Nat. Sei. Philadelphia, pp. 144 145. 



Reviscd Generic Diagnosis. 



PP) 5; 1. post. 1>, post. Ii and r. »nt. B pentagonal; r. post. B and 1. ant. B. tetragonaL 

 III! 5; 1. post. P and ant. 1! large, of irregular shape but roughly four-sided, resting on BB; 

 1. ant. K small, roughly threesided, not touching BB; r. post. R and r. ant. P small, of 

 irregular shape, roughly four-sided, supported between large PP and K', not touching BB. 

 Radial facets equal in size. Arms 5, simple, unbranched; ossicles long, of somewhat tri- 

 angulär section, with large ventral groove from which the axial canal is not separated. 

 R' heptagonal but of roughly five-sided appearance; rests on post. P, r. post. P> and r. ant. B, 

 between 1. post. K and ant. P, while its upper sides support r. post. P and r. ant. R,. Anal x 

 clongate; rests on truncated processes of 1. post. R and r. post. P, abutting against the first 

 brachials: it is followed by a series of similar plates, all very like the brachials in extcrnal 

 appearance and section. Stem round, with low ossicles at least in proximal region; lumen 

 small and apparently round. 



The rather unfortunate treatmenl which this genus bas hitherto met with at the 

 hands of Enropean [»aheontologists would, in anv case, have necessitated a discussion of 



') Structure, Classificatioii and Arrangcmenl of American Palteozoic Crinoids Av. Amer. Geol. vol. VI, 

 p. 35»; ; Minueapolis, Dec. 1890. 



