163 



2 1. L. mediterranea Mer. jìlg. 14]. 



Valve hroad, cuneatc, with its maximal breadlh ncar the upper 

 end, graduali}' attenuated towards the inferior apcx. Pseudoraphe 

 rather broad, very distinct; striae distinct, not very coarsc, compo- 

 sed of rather distinct elongated puncta, number of striae 11 in o.oi 

 mm. in the middle, 14 at the upper part, slightly radiate near the 

 summit. Girdle face moderately broad, with upper angles rounded. 

 Septa moderaily deep (0.0057 mm.), strong, arcuate, septal puncta 

 rather indistinct, secondary puncta large. Length o.oó35-o.o73 mm., 

 breadth of the girdle face o.02 2-o.o35 mm , breadth of the valve 

 0.0 14-0.0 17 mm. 



Locality: Mediterranean (Villefranche), not rare. 



The form of the valves differs but little from that of L. Ehren- 

 bergii, but the size is smaller and the striae much finer and by far 

 not so robust. The girdle face is quite different. The size is rèmar- 

 kably Constant (compare the extremes in the size as shown by 17 

 measurements with those of L. bastata or L. subundulata). 



22. L. mediterranea var. adriatica Mer. [fig. i5]. 



Differs from the type species by its somewhat larger and more 

 variable size, by the greater breadth of the valves and their more 

 rounded superior apex; the striae are a little coarseh and more dis- 

 tant, being io in the middle, 10-12 at the summit; the septa are 

 a little deeper (o.ooò65-o.oo855 mm.) and less arcuate. Length o.o655- 

 0.108 mm., breadth of the girdle face 0.0275-0.032 mm., breadth of 

 the valve 0.016-0.024 mm 



Locality: Adriatic (Ancona), rather common. 



This form greatly resembles L. mediterranea, differing however 

 by quite a number of particularities, which taken separatly are insi- 

 gnifìcant but as a wholc make it necessary to separate this form from 

 the type species. 



(Contiti.) 



