328 



CLAVICULA. 



Valves 



with 



apices 



similar. 



Valves 

 with 



apices 



dissimilar, 



the 



inferior 



attenuated 



like 

 a wedge. 



Tribe IX. Raphoneide^;. 



Valves elongated, with apices inflated, puncta interrupted by 

 two hyaline lines ..... 



Clavicula. 



Frustules usually solitary, with girdle face quadrangular or 

 linear. Valves with pseudo-raphe of greater or less breadth Raphoneis. 



I 



Frustules united in twos, attenuated between the middle and 

 apices ; suture serrated ; valves with coarse puncta without 

 a distinct pseudo-raphe .... 



Girdle face rectangular, the valve only differing from that of 

 true Raphoneis by its inferior apex being cuneate . 



Terebraria. 



Trachysphania 



Girdle 



face 



cuneate. 



( Valves with small terminal pseudo-nodules 



without pseudo-raphe . . Peronia. 



No 

 pseudo- 

 nodule, 

 but a 

 pseudo- 

 raphe. 



GENUS 47. 



Valves gomphonemoid, normal 

 puncta . . . Sceptroneis. 



Valves with coarse round mar- 

 ginal beads . . Grunoviella. 



Valves with coarse puncta very 

 elongated into the form of 

 button-holes . . Opephora. 



-CLAVICULA PANT., 1886. 



,'^r 



[ecnf 



oo^ 



cAPo 



:<>> 



["to { 



Valve with apices inflated, inflations more 

 or less rhomboidal ; coarse puncta leaving a 

 hyaline line on each side of the valves. 



This genus consists at present of a very small 

 number of fossil species found in Hungary by Dr. 

 Pantocksek and of some others, also fossil, from 

 Japan, described by Professor Brun. 



(After a Photograph). 



Fig. 82. 



Clavicula polymorpha 

 var. delicalula. 



