1881.] NATURAL SCIENCES OP PHILADELPHIA. 3*75 



Column pentagonal, central canal very small. 

 Geological Foaition, etc. — L ampler ocrinus is only known from 

 the Niagara group of America. 



1S61. lampterocrinus inflatus Hall. (Balancer, inflatus) Geol. Rep. Wis. (Rep. 

 of Progress), p. 22; Lampterocr. inflatus, ISfiS, 20th Rep. N. Y. St. Cab. 

 Nat. Hist., p. 328, PI. 10, fig. 6. Niagara gr. Racine, Wisconsin. 

 This species is described from internal casts, but there can be no doubt as to its 

 generic identity ; the sptcific characters, however, are undeterminable. 

 1360. Lampterocr. Tennesseensis Roemer. T^vpe of the genus. Silur. Fauna 

 West. Tenn., p. 3", PI. 4, figs. 1 a, b. Niagara gr. Western Tennessee. 

 Si/n. Balancer, sculptus Troost, 1850. Catalogue name. 



7. SAGENOCEINTIS Angelin. 



1843. Austin. Ann. and Mag. Nat. Hist. (ser. i), xi, p. 205. 

 1857. Pictet. Traite de Paleont., iv, p. 323. 



1878. Angelin. Iconogr. Crin. Suec, p. 8. 



1879. Zittel. Handb. d. Palaeout., i, p. 375. 



Syn. Rhodocrinus (in part) Miller, 1821; Actinoerinus (in part) 

 Phillips, 1839 ; Salter, 1859, Olyptocrinus d'Orbigny (not Hall), 

 1850, Prodr., i, p. 46. 



Syn. Megistoerinus Angelin (not Owen and Sliumard), 1878, Iconogr. 

 Crin. Suec, p. 8. 



The genus Sagenocrinus was based upon a species from Dudley, 

 England, which had been referred by Miller to his Rhodocr. 

 verus. and which he believed to occur both in the Subcarboniferous 

 and the Upper Silurian. The Subcarboniferous specimens are 

 now conceded to be distinct, constituting the type of Rhodocrinus, 

 and the}" have in contrast to the Silurian forms the arms con- 

 structed of double joints. The Silurian species, with three 

 underbasals and single arm joints, was separated by Phillips as 

 Acfinocr. expansus, and in 1843 was made by Austin the type of 

 Sagenocrinus. Miller's figure -. p. 106, is evidently ideal, made 

 up from the arms of Sagenocr. expansus, and the body of 

 Rhodocr. verus. The body in the former has perfectly smooth 

 plates, and the latter has certainly not single-jointed arms, as 

 these do not occur in this family beyond the Silurian. Sageno- 

 C7'ini(s differs from Rhodocrinus in having onlj' three underbasals, 

 in the form of the body, and in the arm structure. It is possible 

 that Wirtgen and Zeiler's Rhodocr. gonatodes is a Sagenocrinus 

 if not a Thylacocrinus. The species is only known from casts. 



Austin places Sagenocrinus with the Periechocrinidae, Pictet 

 with the Actinocriniens, Angelin in a family by itself, which he 



