24 LINNARSSON.. BRACHIOPODA OF THE PARADOXIDES BEDS. 



Acrothele granulata n. sp. 



Pl. IV, fig. 51 (and 52?). 



Almost circular, a little wider than long. Ventral valve 

 slightly conical. Umbone pointed, very excentric, the distance 

 from the front being about four tiraes that from the posterior 

 margin. Its shape cannot be exactly defined from the mate- 

 rials hitherto obtained. Of a false area there is hardly more 

 than a slight trace, only a very narrow space between the 

 umbone and the posterior margin showing a slight difference 

 from the other parts of the shell. The anterior part of the 

 valve is depressed. The inner shell layers are smooth and po-, 

 lished, the outermost one opaque, granulated and marked near 

 the circumference by concentric lines of growth. The interiör 

 is vmknown as well as the dorsal valve. The only specimens 

 of the ventral valve measure: 



Length 8 mm. Breadth 9 mm. 

 » 8,. 5 » » 10 » 



» 9,.^ » » 11 » 



Though the scanty materials give but an imperfect know- 

 ledge of this species, it cannot be questioned that it is very 

 nearly allied to A. coriacea. It seems, however, to be distinct 

 by having the vimbone more pointed and excentric, the snrface 

 distinctly granulated, and the false area hardly indicated. It 

 is also, upon the average, larger. 



Acrothele coriacea has ~ been found in Jemtland at Lillviken 

 near Östersund, and in a section at the river Billstaån in the 

 parish of Hackas. The rock which has yielded -it probably 

 belongs to the strata with Paradoxides ölandicus. ') 



In the island of Öland Dr. Wallin has found, near Borg- 

 holm, in the strata with Paradoxides ölandicus one single dorsal 

 valve (fig. 52) the sculpture of which resembles that of the 

 ventral valves from Jemtland above described, and Avhich may 

 possibly belong to the same species. This valve is, however, 

 more transverse, its length being 10, its breadth IS mm. It 

 is gently and uniformly convex, not so flat as the dorsal valve 

 of A. coriacea, but I do not think it impossible that its ori- 

 ginal shape has been somewhat altered. 



') Cfr. ante, p. 6. 



