14 LINNARSSOX, BKACHIOPODA OF THE PARADOXIDES BEDS. 



probable that it will tum out to be an independent species, when 

 sufficient materials have been obtained. 



The ventral valve, judging from the internal cast, is mode- 

 rately and evenly convex. The area is not seen in the cast, but 

 it seems to be much lower than in the preceding species. The 

 muscular depression is small, surrounded by a raised börder, to 

 whicli, in the cast, corresponds a depression. The internal cast 

 is covered with a few sharp, distant, radiating ribs. with concave 

 interspaces. ^lost of them extend from the mnscular depression 

 to the margin. Between these only a few shorter ribs are in- 

 terpolated. — The dorsal valve is nearly semicircular, or semi- 

 elliptical, gently convex, with a sliallow longitndinal depression 

 extending from the innbone to the front. In the interiör the 

 small Cardinal process is situated between two widely divergent 

 brachial plates. The muscular scars are strongly marked and 

 separated by a wide mesial ridge, which extends from the car- 

 •linal process to the iront. The anterior pair are oblong, lon- 

 gitudinal, the posterior more rounded. The internal cast, like 

 that of the ventral valve, is covered with distant, sharp, angular 

 ribs, the number of which, near the anterior margin, is about 20. 

 Two dorsal valves measured: 



Length (5 mm. Breadth 9 mm. 



In most respects this species, as has already been stated, 

 bears a great analogy to the preceding one, especially to such 

 examples as fig. 16. The most important difterences are, as far 

 as can be judged from the imperfect materials, the following. 

 The ventral valve is less convex, and the muscular depression in 

 its interiör not so distinctly trilobed as in the preceding species. 

 The dorsal valve, on the contrary, seems to be somewhat deeper 

 than in the preceding, and the muscular scars are more strongly 

 marked. The radiating ribs, at least on the internal casts, are 

 fewer, stronger, and more angular. In this latter respect it agrces 

 more with O. Hicksi, the valves of which seem also to have a 

 similar form. Their relation cannot, liowever, at pi-esent be ascer- 

 tained in a satisfactory manner. 



This species seems to be conlined to the strata with Para- 

 doxides Forchhammeri. I have only found it at Kinnekulle and 

 Lovened in Westrogothia, and at Södra Möckleby in the island 

 of Öland. 



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