22 BRITISH DIATOMACE^. 



Forfar, at an elevation of 2800 feet. Near Aberdeen and near Belfast, 

 Br. Dickie ; Rescobie, Mr. P. Grant. Marl, Co. Down, &c. 



Plate III. 33. d. outline of ditto in S. V. 



4. Cocconeis Scutellum, Ehr. V. orbicular or elliptical; striag 

 concentric with extremities, moniliform, 18 in "OOl". Length 

 •0006" to -0016". v.v. 



/3. Nodule dilated into a Stauros. 

 Ehr. Inf. xiv. 8. Kutz. Bacill. v. 6. 



Marine. Very common, and exceedingly variable in size and outline. 

 Plate III. 34. /3, Supp. Plate XXX. fig. 34. 



5. Cocconeis Grevillii, n. sp. V. oval, furnished with transverse 

 canaliculi; striee moniliform, 15 in -001". Length -0008" to -0025". 

 v.s. 



Quek. H. C. pi. xii. 19? 



Marine. Attached to Phyllophora riibens, Sidmouth, communicated by 

 Dr. Greville. Hastings, Mr. Shadbolt. Poole Bay, W. Sm. (Algoa Bay, 

 South Africa. Ichaboe Guano.) 



Plate III. 35 a. lower valve ; 35 a*, upper valve ; 35 «'. ^iew of upper valve 

 from within. 



6. Cocconeis diaphana, n. sp. V. elliptical, scarcely siliceous, dia- 

 phanous; striae obscure. Length •0012" to •0018". v.v. 



/3. Nodule dilated into a Stauros. 



Marine. Sidmouth, Miss Cutler, communicated by Dr. Greville. Pontac, 

 Jersey, Aug. 8, 1852, W. Sm. 



Supp. Plate XXX. 254. 



Genus 6. COSCINODISCUS, Ehr. 



Frustules free or adherent, disciform ; valves plane or slightly convex 

 with a cellular structure. 



This genus, though closely related to those which immediately 

 follow it, finds its nearest allies in the Melosirece, whose genera, from 

 their filamentous character, stand widely apart in the present work. 



