14 BRITISH DIATOMACE^. 



1 1 . Epithemia Musculus, Kiitz. V. regularly and highly arcuate, 

 extremities acute; canaliculi distant; striae 40 in -001". v.v. 



Kiitz. Bacill. xxx. 6. 



Brackish water. Poole Bay. " Little Sea," Dorsetshire, Aug. 1848. Near 

 Lewes, Sussex, Sept. 1850, W. Sm. 



Plate I. 10. 



12. Epithemia Westermanii, Kiltz. F. V. elliptical; V. arcuate; 

 canaliculi distinct; striae faint, 40 in 'OOl". Length '0008" to 

 •0013". v.v. 



Kiitz. Bacill. v. 12? Eunotia Westermanii, Ehr. Inf. p. 190. taf. xiv. 6? 



Brackish water. Near Lewes, Oct. 1850, W. Sm. (Ceylon, Mr. Thwaites, 

 Nov. 1851.) 



Plate I. 11. 



13. Epithemia rupestris, n. sp. F. V. elliptical-lanceolate ; V. 

 acute, slightly arcuate; canaliculi distant, 6 in 'OOl" ; strife faint, 

 42 in -001". Length -0012" to -0023". v.v. 



Fresh water. Backsbottom near Lancaster, Mr. G. Smith, April 1851. 

 Plumpton, Sussex, April 1852, 7F. Sm. Aberdeenshire, !>/■. Dickie. Killi- 

 crankie, Mr. P. Grant. Raasay Earth. 



Plate I. 12. 



The above species first fell under my notice in a gathering made by Mr. G. 

 Smith from the surface of a rock moistened with water in the habitat I have 

 mentioned ; its frequent occurrence in other localities shows that it is widely 

 distributed in subalpine districts. Together with the species last described, 

 and the three which follow, its valves present a peculiar form : their convexity 

 is so considerable, that a transverse section of the frustule would furnish an 

 outline not unlike the figure 8, owing to which circumstance a side view is with 

 difficvdty obtained, the frustules naturally presenting their broadest surface to 

 the eye. 



14. Epithemia constricta, n. sp. F. V. elliptical with a more or 

 less distinct constriction ; V. acute, much arched ; canaliculi distant, 

 8 in -001"; strice 30 in -001". Length -0012" to -0026". v.v. 



" Ep. constricta," cl. De Brebisson in litt. cum specim. 

 Brackish water. Excet, Sussex, March 1852, JF. Sm. 

 Supp. Plate XXX. 248. 



