Om Skånes brachiopodskiffer 
95 
Bollia biplicata n. sp. 
PI. II, f. 21—22. 
Carapace strongly convex a little longer than high. Hinge line short and 
straight, end margins and the ventral one strongly curved. A linear indistinct 
marginal border surrounds the convex outline of the valve. On the anterior two 
thirds or on small specimens more in the middle of the valve there are as on 
Bollia harparum two transverse strong ridges of equal height, at the base of which 
an obscure connection may be noticed. While the deep vertical sulcus between 
the lobes has an oblique forward direction the anterior lobe becomes shorter than 
the posterior which is also bent, and on adult specimens both the lobes get the 
same average direction as the sulcus. On young specimens, however, where the 
sulcus is broader the lobes are straighter and more vertical like those of- Bollia 
harparum. A faint furrow surrounds the horse-shoe- or U-ridge, but mostly only 
its vertical ends are visible. Outside this furrow the carapace is awollen forming 
a broad callosity, most marked in its dorsal ends, especially the anterior one. — 
For the measures see p. 56. 
Jonesina rectangularis n. sp. 
Text fig. 9, p. 57. 
Carapace subrectangular, the longer margins being almost straight, the ventral 
one, however, a little curved in. its ends. The two posterior angles are right, the 
lower one being rounded; anterior margin strongly curved. The valve is bordered 
both ventrally and on the ends by a faint raised line, sometimes also visible 
along the hinge line. The surface is raised into a broad curved ridge, forming 
a lying extended C, divided by a vertical and a horizontal sulcus into four lobes, 
the upper ones — especially the post-dorsal one — being the highest. For the 
measures see p. 56. 
This Ordovician species may be referred to the genqs Jonesina Ulrich & 
Bassler, before thought to be only of Carboniferous age. It is very like the Ame- 
rican species J. bolliaformis Ulr. & Basse. 
