6o OLAF HOLTEDAHL. M.-N. Kl. 



Although a good deal of variation is seen in this material, in size, 

 outline, development of sinus and fold and coarseness of striation, I do 

 not think that any distinct varieties, characterised by fairly constant fea- 

 tures, can be found. Even specimens from the same beds may vary 

 rather strongly. The majority of specimens are relatively flat, much like 

 the one depicted pi. X, fig. 9, but we have also very strongly curved ones. 

 In 6 c the specimens are sometimes very convex, and of very large size 

 (see pi. X, fig. 6—7). 



Interiors of both ventral and dorsal valves are observed and show 

 the same features as seen in Davidson's figs. 12 — 13. No denticulation is 

 seen in the cardinal areas 



Occurrence. Total vertical range 6 a— 8 c, found in Ringerike, 

 Asker, Bundeijord and Is), oft". Holmestrand. 



Strophomena Loveni Vern. 

 (PI. XIII, fig. 5). 



1848. Leptœna Loveni Verneuil, Notes sur quelques brachiopodes de Tile de Gothland. 



Bull. See. Géol. France, 2 Ser. Vol. 5, p. 339 pi. IV, fig. 5. 

 1 86 1. Strophoniena Loveni Lindstrøm, Gotl. Brach, p. 371. 



Mat. pres. A single fairly complete specimen, besides minor frag- 

 ments. 



Description. Size very small, exact outline not seen, broadly rounded 

 in front, cardinal extremities broken. Ventral valve slightly convex in 

 posterior part, with a well marked rounded sinus in front. Dorsal valve 

 rather flat in longitudinal direction, with broad median elevation sloping 

 gradually till lateral margins. 



Surface markings very delicate. A series of exceedingly fine radiating 

 ribs cross the surface with moderate intervals, and in some places there 

 are indications of still finer striae between those mentioned. The most 

 visible surface ornamentation consists however of a large number of very 

 small irregular depressions scattered over the surface. Near the hinge 

 line these are more continuously arranged, forming very delicate, not very 

 distinct corrugations directed strongly outwards. A concentric line of 

 growth is seen not far from the beak in the best preserved specimen, 

 equally far in both valves. 



Cardinal area of dorsal valve very small, ventral much larger, angle 

 between them rather acute; deltidium distinctly convex. The cardinal areas 

 as seen in exterior view are smooth. 



