402 ME. F. A. BATHER ON PETALOCEINTJS. [Aug. 1 898 



Now that Mrs. Davidson's more complete individuals have been 

 described, and the genus erected on their broader basis, it is time to 

 describe the three species found in Gotland. The knowledge gained 

 from them may then be applied to the elucidation of the special diffi- 

 culties presented by the American specimens, and to the establish- 

 ment in our classification of the family Petalocrinidae, which, though 

 suggested, was neither defined nor discussed in the paper just 

 mentioned. Mr, Stuart Weller has obtained from various American 

 localities fresh material of the species described by him and of two 

 other species, and it was his intention to publish a supplementary 

 paper with some revision of his previous work. He has, however, 

 with the utmost generosity, placed his material in my hands for 

 description, and helped me with notes, photographs, and plaster casts. 

 Mrs. Davidson, too, was so good as to bring the type-specimens 

 and other material to Loudon with her in June 1897, in order 

 that my study might be as complete as possible. This kindness 

 from America fully repays the patience of seven years. But if 

 there be any value in this paper, thanks are due not only to 

 Mrs. Davidson and Mr. AVeller, but to Prof. Gustaf Lindstrom for 

 affordiog every facility for the examination of the specimens in the 

 Riksmuseum at Stockholm, to my wife for much assistance in the 

 wearisome preparation of those specimens, and to Mr. Gustaf 

 Wenman for the pains that he has taken in the production of the 

 plate illustrating them. 



II. Geological Relations of PetalOcminus. 



The species herein described are : — 



P. mirahilis, Weller ; Niagara Limestone : Jones Co. (Iowa). 



P. inferior, n. sp. „ „ „ 



P. longus, n. sp. „ ,, St. Paul (Tndiana). 



P. vi&bycensis, n. sp. ; beds b & C (Lindstrom) : north of Wisby (G-otland). 



,, (senior) ; tipper part of C : Weslergarn (Gotland). 



P. angusius, n. sp. ; junction of b & c ; north of Wisby (Gotland). 

 P. expansus, n. sp. ; base of f : Wisby (Gotland). 



P. inferior and P. mirahilis are both found near Monticello, but 

 not in absolutely the same locality, and the former, according to 

 Mr. Weller, is at a slightly lower horizon. P. vishycensis and 

 P. angusius are found in the clay along the shore north of Wisby ; it 

 is not possible to refer each specimen to a definite horizon, but they 

 may, generally speaking, be regarded as occurring at a horizon 

 equivalent to the junction of the Llandovery and Wenlock series in 

 England, or the Clinton and N'iagara groups in IN'orth America. 

 Since a species is also found at the base of Lindstrom's bed f (that is, 

 somewhere about the Lower Ludlow of England and the Onondaga 

 of Xorth America), it follows that the known range of the genus 

 extends both earlier and later in Gotland than in Iowa and 

 Indiana, 



Mr. Weller, in 1896, when still ignorant of the occurrence of 



