BRACHIOPODA. 107 



Genus LINNARSSONIA, Walcott. 1885. 



PLATE III, FIGS. 35-44. 



1866. Oholella, Discina, Saltkk. Rept. British Association for 3865, p. 285. 



1868. Obolella, Davidson. Geological Mag'.izine, vol. v, p. iJ09. 



1868. Obolella, Habtt. Dawson's Acadian Geolog-y, Second Edition, p. 644. 



1871. Oholella (partim), Davidson. British Silurian Brachiopoda, i:). 339. 



1876. Obolella, Linnarsson. Brachiopoda of the Paradoxides Beds of Sweden, p. 19. 



1885. Linnarssonia, Walcott. American Journal of Science, vol. xxix, p. 115. 



1885. Linnarssonia, Matthew. Illustrations of the Fauna of the St. John Group, No. 3, p. 35. 



1887. Linnarssonia, Walcott. American Journal of Science, vol, xxxiv, p. 189. 



1889. Linnarssonia, Dawson. Transactions Royal Society of Canada. 



Diagnosis. " Shell calcareous, transversely or longitudinally ovate, subcir- 

 cular ; convex in the typical species ; valves inarticulate. Ventral valve 

 convex, with the excentric apex perforated by a minute foramen ; no area ; 

 cardinal edge thin. Dorsal valve convex in the species thus far known ; with- 

 out any area. In the interior of the ventral valve two oval and oblique scars 

 lie each side of the slightly raised rim surrounding the minute foraminal 

 opening and close to the posterior margin ; from the foraminal rim a groove 

 extends obliquely forward and outward on each side, so as to enclose a project- 

 ing y\-shaped ridge that is highest at its posterior margin just in front of the 

 circular foraminal opening. In the interior of the dorsal valve two large, 

 irregularly circular scars are situated close to the posterior margin, and separated 

 by a low, flat ridge that extends forward, between the two small divaricator 

 scars."* 



Type, Obolella transversa, Hartt. 



Observations. The illustrations of the internal characters of this genus, 

 which have been given with great elaboration by Mr. Davidson,! for Obolella 

 sagittalis, Salter, and also with instructive figures, by Dr. Linnarsson,j: for the 

 same species; by Mr. Walcott, for the type of the geiius,§ L. transversa, 

 Hartt, and for L. Taconica, Walcott,|| and by Mr. G. F. Matthew,1I for the 

 species L. transversa, Hartt, and L. misera, Billings, all produce the impression 



* Walcott. American Journal of Science, vol. xxix, p. 115. 



t Geological Magazine, vol. v, pi. xv, figs. 17-24; Silurian Brachiopoda, pi. 1, figs. 1-14. 

 J Brachiopoda of the Paradoxides Beds, jil. iii, figs. 36-41. 

 § American Journal of Science, 1885, vol. xxix, p. 116. 

 1 American Journal of Science, 1887, pi. i, figs. 18 h-H.. 

 1[ Illustrations of the Fauna St. John Group, 1885, \>\. v, fig. 11 a-e, 12a-e. 



