428 DIATOM ACEiE. 



species of the genus Cymhella : N. amphora Ehr., N. lineolata 

 Ehr., and N. JVestermanni. 



1. Cymbella zebea Hass. 

 Plate C. Fig. 8. 



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



front aspect elongated, quadrangular, zcith straight sides. 



Strise distant, strongly marked, double. 

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



Berlin, p. 262. ; Bericlit. der Akademie d. Wissensch. 



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



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

 Hob. 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 strite, 

 which in Eunotia zebra 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 tuegida Ilass. 



Plate C. Fig. 7. 



Char. Frustules semi-lanceolate, truncate at either extremity 

 in side view ; in lateral aspect narroioer toioards 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. 



Hab. Storrington Common : 3fr. Jenner. 



This species needs only to be contrasted with Cymbella 

 zebra, from which it differs in the two particulars indicated 

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



