147 

 towards the upper end which is slightly rostrate, thcn again slightiy 

 inflated at the lower part, inferior apex acute, often rostrate. Pseu- 

 doraphe broad, striae robust, usually 8 (8-10) in 0.01 mm. throughout. 

 Septa net deep, 0.0057-0.0067 in length. Length 0.12Ó-0.22Q mm., 

 breadth of the valve o.oi3-o.o38 mm., at the constriction 0.0095-0.022 

 mm., at the lower inflated part 0.0105-0.024 mm. 



Locality: Adriatic (Triest, Fiume, Quarnero, Ancona), not very 

 common ! fossil : Kertsch, Crimea (Sarmatische Stufe), not very com- 

 mon. 



This beautifull form is very variable in its outlines and gradualiy 

 passes into var. fnngoides and var. ovata on the one band and into 

 L. ansustata Grun. on the other. 



10. L. Ehrenbergii var. tenuistriata Mer. 



Valve of the same form as in the type species but the striae 

 much tìner and a little closer, 10 in 001 mm. throughout, puncta 

 very indistinct. Septa not profound, c.ooòóS mm, deep. Length about 

 0.1 ig, breadth of the valve o. 024-0. 025ò mm. 



Locality : Samoa, rather rare ! Hawaii, rare. 



From New Guinea I know a form with stili finer striae (10-11 

 in 0.0 1 mm.) and with valves resembling more those of forma bar- 

 badensis than of the genuine L. Ehrenbergii. Wether this is the same 

 as var. tenuistriata of Samoa or a separate variety cannot be deci- 

 ded without further observations. 



II. L. elegans Mer. [fìg. 4]. 



Valve broad, davate, very gracefuUy shaped, abruptly attenuated 

 in the middle or towards the lower '/g, gradualiy tapering from this 

 point toward the inferior apex which is narrow, upper end slightiy 

 attenuated, with rounded summit. Pseudoraphe broad, striae very dis- 

 tinct but fine, with rather distinct puncta, 10 to 11. 5 in o.oi mm. 

 in the middle part, radiant at the summit. Septa sballo w, their length 

 0.0024-0.0038 mm. Length o.o855-o.i23 mm., breadth of the valve 

 0,020-0.0266 mm. 



