37 



gles sliyhliy rounded, outlines delicate; septa deep (o.oo33 mm.), 

 thin, faintly arcuate, septal puncta small, round, very distinct. En- 

 dochrome granular. Length o.o25-o.o53 mm„ breadth of the girdle 

 face 0.007Ò-0.017 mm., breadth of the valve o.oo43-o.oo55 mm. , 



Locality : Black sea (Goursouf, Crimea, rather common) ! Mediter- 

 ranean (Villefranche), rare. 



This curious species has valves partly symmetrical, partly asym- 

 metrical. both lypes being about of the same frequency. It is cer- 

 tainly nearly related to L. proboscidea Aler., but the valves of the 

 latter are never asymmetrical, the proboscis or rostrum is usually 

 much more distinct, the septa in the average are deeper. 



38. L. spicula Aler. [fig. 28]. 



Valve exstremely narrow, spicula like, slightly attenuated from 

 the upper third to the summit which is rounded, upper part so- 

 mewhat produccd ; gradually attenuated towards the inferior apex, 

 the latter acute. Striae very fine. Girdle face narrow, cuneate. with 

 upper angles subacute, outlines delicate; septa deep (o.o52 mm.), 

 very thin, bccoming stronger above the septal puncta, where thev 

 are but very sliglitly divergent, septal puncta very small. Forming 

 small colonies of from 2 to 8 individuals on short dichotomeously 

 divided stipes. composed of two layers, the inner being thinner but 

 denser than the outer. Length o.o38-o.04Ó6 mm., breadth of the girdle 

 face 0.0067-0.0076 mm., breadth of the valve 0.0024-0.0029 mm. 



Locality: Adriatic (Pola), rather common. 



This species has the most narrow valves known, the other ex- 

 treme being represented by L. Baileyi Lewis. The somewhat rostrate 

 upper end of the valve reminds L, proboscidea ; further examination 

 might prove it to be a variety of the latter. As is stands now I see 

 howewer no suQìcient reason to consider it as such. 



39. L. subundulata Mer. [tìg. 2 )]. 



Valve very narrow, bacilliform, with one or two usually faint con- 

 strictions. very slightly attenuated towards the inferior apa\ wilh aU 



