240 Systematic Paleontology — Middle Devonian 



sented by fig. 18 on pi. xlix from the vicinity of Cumberland is rather 

 shorter than the majority of specimens of this species and it is almost of 

 the same size and proportions as the Williams Eoad specimen. This 

 species is closely related to P. tenuistriata Hall and P. muta Hall but is 

 separated by its fine concentric striae, some of which become elevated into 

 sharp lamellae, with finer intermediate ones on the posterior part of the 

 shell. The striae of P. tenuistriata as compared with P. fecunda are 

 finer and more irregular becoming crowded together on the posterior part 

 of the shell, while in P. muta the strong, lamellose striae extend from the 

 posterior to the anterior margin of the shell. 



Length, 25 mm. ; height, 16 mm. 



Occurrence. — Eomney roRMATiON, Hamilton Member. Williams 

 Eoad \ mile east of Queen City Hotel, Cumberland. 



Collections. — Marjdand Geological Survey; New York State Museum. 



Palaeoneilo peeplana var. grabaui n. var. 

 Plate XXVI, Figs. 22, 23 



Description. — Shell rather large, length less than twice the height; 

 basal margin curving; umbonal slope marked by two ridges separated by 

 a conspicuous sulcus. Entire surface marked with regular, strong, ele- 

 vated lamellae extending from the anterior to the posterior extremities, 

 between which are fine striae. 



The specimen upon which the above description is based is an external 

 impression of a right valve which is broken and somewhat imperfectly 

 preserved. It differs clearly from P. perplana in the conspicuous lamellae 

 extending entirely across the shell from its anterior to the posterior end 

 while in that species they " are usually obsolete, except on the posterior 

 portion of the shell." ' Neither does it agree any more closely with any 

 other species. Professor Grabau who examined the specimen wrote me 

 as follows : " It comes nearest to P. perplana of the New York beds, 

 but is more rugose and has a somewhat deeper umbonal channel, though 

 I think much of the apparent depth of this is due to crushing. It would 



' Hall, Lamellibranchiata il, p. 339. 



