66 BRITISH DIATOMACEiE. 



Fresh water. Pentland Hills, Dr. Greville. Near Silverdale, Lancashire, 

 Dec. 1855, Mr. Johnson. 



This interesting form was first collected by Dr. Greville in the above locality, 

 and is well distinguished from all the other species of this genus by its coarser 

 moniliform striae and cuneate ends. 



Supp. Plate LXII. 389. 



Genus 52. DICKIEIA, Ralfs. 



Frond membranous, leaf-like; frustules imperfectly siliceous, scat- 

 tered, naviculoid, oblong ; valves elliptical, striated. 



This genus is easily distinguished from the last, from which it 

 differs in the character of its frond, as well as the structure of its 

 frustules. Nor is it likely to be confounded with any subsequent 

 genus, its flat leaf-like form, and the irregular and scattered arrange- 

 ment of the imbedded frustules being peculiar. 



1. Dickieia ulvoides, Ralfs. Frond entire, linear, or obovate, with 

 a distinct pedicel; valves elliptical; nodule more or less stauri- 

 form ; striae 36 in -001". Length of frond -3" to 1'4". Breadth of 

 frond -06" to -4". Length of frustule -0010" to -0013". v.s. 



Berk, and Ralfs, Ann. ser. 1. vol. 14. pi. ix. Prit. Anim. xxiv. 31. Kiitz. 

 Bacill. p. 119; Sp. Alg. p. 109. 



Marine. Near Aberdeen, April 1844, Dr. Dickie. 



Plate LIV. 342. 



2. Dickieia pinnata, Ralfs. Frond irregularly divided; divisions 

 rudely pinnate or laciniated ; valves elliptical-lanceolate ; nodule 

 punctate. Length of frond "3" to 1*1". Breadth of frond "l" to 

 •6" ; striae 40 in -001". Length of frustule -0009" to -001 1". v.s. 



Ralfs, Ann. ser. 2. vol. 8. pi. v. 6. 



Marine. Near Aberdeen, Sept. 1851, Dr. Dickie. Cumbrae, March 1853, 

 Mr. Kennedy ; communicated by Dr. Arnott. 



Plate LIV. 343. 



