I 



428 DIATOMACEiE. 



Species of the genus Cymhella : JV. amphora Ehr., N. lineolata 

 JEhr., and N. Westernianni. 



1. Cymbella zebka Hass. 



Plate C. Fig. 8. 



Char. Frustules in side view semi-lanceolate, truncate ; in 

 front aspect elongated, quadrangular, icith straight sides. 

 Strias distant, strongly marked, double. 



Navicula zehra, Abhandl. der Akademie d. Wissensch. zu 

 Berlin^ p. 262. ; Bericht. der Akademie d. Wissensch. 

 zu Berlin, 1837, p. 53. Eunotia zehra Ehr., Die 

 Infus. p. 191. pi. xiv. fig. 7. pi. xxi. f. 19. 



Hah. Cheshunt : A. H. H. On the moist conglomerate 

 sandstone cones near Cushendall, co. Antrim : Mr. 

 Moore. 



This fine species approaches rather closely to the following, 

 from which it differs however in two respects ; in the stride, 

 which in Eunotia zehra are less numerous than in E. turgida, 

 and in the form of the frustule, which in the front view is 

 not attenuated at the extremities as it is in that species. 



2. Cymbella turgida Hass. 



Plate C. Fig. 7. 



Char. Frustules semi-lanceolate ^ truncate at either extremity 

 in side view ; in lateral aspect narrower towards either 

 end than in the centre. 



Navicula turgida, Abhandl. der Akademie d. Wissensch. 

 zu Berlin, 1830. Eunotia turgida, Bericht. der Aka- 

 demie d. Wissensch. zu Berlin, 1837, p. 45. ; Die Infus. 

 p. 190. t. xiv. fig. 5. 



l»/ Hah. Storrington Common : il/r. t/^?^^^er. 



This species needs only to be contrasted with Cymhella 

 zehra, from which it differs in the two particulars indicated 

 in the description of that species, viz. in its finer and closer 



