NO. 2.] DESCRIPTION OF THE FOSSILS. 57 



The figure in question is the copy of a drawing to which Davidson J formerly gave 

 the name of Lingula Beani Phill., but which was subsequently 2 identified by 

 the same author as belonging to the Liassic species Lingula sacculus Dew. 



In one of the specimens of Lingula Beani Phill. from Yorkshire, a suc- 

 cessful preparation brought out the muscular impressions of the larger valve 

 quite distinctly. The impressions of the anterior adductors and of the external 

 protractors are considerably deeper here than in our specimen from the neigh- 

 bourhood of Cape Flora. The posterior margin of these impressions, in the 

 British specimen also, is not entire. It exhibits three incipient lobes directed 

 backwards, but all less distinct than in the Arctic specimen. In the British spe- 

 cimen, the middle lobe is broader and shorter, those on each side of it smaller, 

 and the curves shorter and shallower than on PL I. fig. 4. In specimens 

 of the Lingula Beani Phill. from Alsace, the muscular impressions, which are 

 considerably more superficial here than in British specimens, did not allow 

 of being so well prepared. As far as I could see in the Alsace specimens the 

 posterior edges of the muscular impressions (anterior adductors and exterior 

 protractors) are more lobed here than in British specimens, and correspond 

 better with the figure given on PL I. fig. 4. 



It appears from the material examined that the difference in the shape 

 of the muscular impressions probably depends upon the depth which these 

 impressions have had in the valves. After observing this, I have no hesita- 

 tion in identifying the lingulid form from Franz Josef Land, now before me 

 (with shallow, posteriorly deeply lobed muscular impressions) with Lingula 

 Beani Phill. from the lowest Inferior Oolite of England (with deep, only 

 slightly lobed muscular impressions) and from the Sauzei zone of Alsace 

 (with shallow, more deeply lobed muscular impressions), as the size, form 

 and sculpturing of the individuals of the most different localities agree. 



Lingula brevirostris, Meek and Hayden 3 , from the Jura of the Black 

 Hills of Dakota is closely allied to our species by the straight lateral edges. 

 The American species differs from Lingula Beani Phill. in having longer 

 posterior margins and a more pointed umbo. 



1 Th. Davidson, 1850, I. c. pi. I, fig. 1. 



2 Th. Davidson, 1876, 1. c. p. 79. 



8 H. Newton and W. P. Jenny, 'Report on the Geology and Resources of the Black 

 Hills of Dakota, U. States' g. a. g. Surv. of Rocky Mts. Region. 1880. p. 346, pi. III. 

 figs. 4, 5. 



8 



