90 Mr. T. R. Jones on Scandinavian Beyrichiae. 



on the flattened margins of the anterior and posterior dorsal 

 angles of the valve. 



This form abounds in two of the limestones, and is evidently 

 referred to in Kloden's figures 16-18; but it is still better 

 figured by Wilckens, after whom I have named this peculiar 

 species. 



Beyrichia Wilckensiana, yar, plicata, PI. V. figs. 19-21. 



In this variety the anterior dorsal angle is more acute, and 

 the central lobe more compressed, than in the typical form ; and 

 the dorsal portions of the anterior and posterior lobes are marked 

 by short faint vertical furrows, so as to appear pinched up into two 

 or three small projecting angular ridges or plaits. The wrinkle 

 or sulcus bounding the convex part of the valve is rather more 

 strongly marked also. 



This variety does not occur with the foregoing, but is plentiful 

 in No. 1. limestone; and the specimens are usually smaller, 

 though some individuals attain the full size of the type. 



Possibly Kloden^s figure 19. was taken from a specimen of 

 this variety. 



7. Beyrichia siliqua, nov. sp. PI. V. fig. 32. 



Carapace-valve elongate, contracted anteriorly ; smooth ; con- 

 vex; divided into three unequal lobes by two shallow, rather 

 oblique furrows crossing the convexity of the valve. Posterior 

 lobe the largest. Marginal rim well developed on the ventral 

 border. 



Two dextral valves only in one of the limestones represent 

 this well-marked species. 



(SiMPLICES.) 



8. Beyrichia mundulay nov. sp. PI. V. fig. 23. 



Carapace-valves varying from oblong to nearly oval, convex, 

 smooth, punctated, and marked by a short distinct furrow near 

 the middle of the upper part ; the marginal depressed rim nar- 

 row and sometimes obscured on the ventral border by the con- 

 vexity of that part of the valve. 



This occurs in three of the limestones, and from its small size 

 and general appearance is liable to be confounded with the 

 numerous Cy there-like forms so common in these Scandinavian 

 limestones. The specimens from No. 1. limestone are more oval 

 and convex than the others; those from No. 5. are well pre- 

 served, and interesting from their oblong shape, depressed mar- 



