348 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 45. 



GASTROPODA. 



Genus PLATYSCHISMA McCoy. 



PLATYSCmSMA HELICITES (Sowerby). 



Plate 31, figs. 15, 16, and 18. 



1839. Trochus helidtes Sowerby, Sil. Syst., p. 603, pi. 3, figs, le and 5. 

 1888. Platyschisma helidtes (Sowerby) Etheridge, Fobs. Brit. Isl., vol. 1, Pale- 

 ozoic, p. 114. 



This common Ludlow species is represented by numerous specimens 

 in several horizons of the upper part of the Pembroke formation. It 

 has not been detected either in the Edmunds below or the Eastport 

 above, and is therefore, for the Eastport area, a characteristic Pem- 

 broke species. 



Locality. — Hersey red shale member of the Pembroke formation, 

 eastern shore of Hersey Cove, Pembroke Township (loc. No. 2.42.8A 

 and 2. 52. 3 A). 



Plesiotypes.—C&t. No. 58977, U.S.N.M. 



EXPLANATION OF PLATES. 



Plate 29. 



New species from the Edmunds formation of Washington County, Me. 



Figs. 5, 6, 7, 13, 14, 15, 16, 17, 18, natural size. 



Figs. 1, 2, and 4, slightly enlarged. 



Fig. 3, enlarged 2^ diameters. 



Figs. 8, 9, 10, 11, 12, enlarged 2 diameters. 



Whitfieldella edmundsi Williams. 



Figs. 1,2, 4. — Brachial, front and pedicle view of a specimen of ordinary size. 

 Fig. 3. — ^A small specimen, showing the interior spiral arms. 



Locality: East shore of Burnt Cove, south of Cunningham Mountain, Edmunds 

 Township, Washington County, Me. (loc. No. 5.51.5B). 

 Cat. No. 58944. 



Chonetes cobscooH Williams. 



Fig. 5. — Mold of the interior of a pedicle valve, showing a form less transverse 

 than some of the specimens of the species and the finer and more numerous lineations 

 than on Chonetes striatella Dalman. 



Locality: Calcareous shales south of Field Point, Edmunds Township (loc. No. 

 8.21.1A). 



Cat. No. 58949. 



Chonetes edmundsi Williams. 



Figs. 6, 7. — Pedicle and brachial valves normal size. 



Fig. 8. — An enlarged view of a pedicle valve showing spines. 



Fig. 9. — Mold of interior of pedicle valve, enlarged. 



Locality (specimens 6, 7, and 8 from): One half mile south of Field Point, west 

 shore of Cobscook River, Edmunds Township (loc. No. 8.21. lA); Spec. No. 9, west 

 side Burnt Cove, Edmunds Township (loc. No. 5. 51. 5 A). 



Cat. Nos. 58945, 58946. 



