Mr. J. Ralfs on the British Diatomacee. lll 
gated (eight to twelve times longer than broad), not striated ; the 
front view is narrow linear-lanceolate with truncate ends, and 
the lateral surfaces, which are about the same breadth, are lan- 
ceolate with subacute extremities. 
The colouring matter occupies only the central third of the 
frustule, and consequently the ends are hyaline. 
Prare ITI. fig. 2. Berkeleya fragilis: a, front view; 6, lateral view. 
Encyonema, Kiitz. 
Frustules cymbiform, siliceous, arranged in longitudinal series 
within submembranaceous, tubular filaments. 
The filaments are tubular, submembranaceous, and under the 
microscope colourless. The lateral surfaces of the frustules being 
convex are observed in the front view, in which also the frustules 
are quadrilateral with two puncta at each end. These puncta are 
less easily discerned in the dorsal view as the dorsum is longi- 
tudinally convex. The lateral view 1s semi-elliptic with numerous 
transverse striee, which are interrupted as in Cocconema by a lon- 
gitudinal pellucid line. 
This genus differs from Schizonema and other frondose genera 
of Diatomacee in the form of its frustules, as a single frustule 
resembles one of Cymbella or Cocconema ; therefore, notwithstand- 
ing the similarity of habit, it belongs to a different series. 
It is far more probable that some bodies of a totally different 
kind will be at first sight classed with Encyonema. 'These, which 
are really congeries of the ova of certain insects, were once de- 
scribed by Agardh as Algeze under the name of Gloionema. A 
little attention however will secure the observer from this mistake, 
for although eymbiform and arranged in longitudinal series, the 
eggs are neither siliceous nor striated. 
1. E. prostratum, Berk. Kutz. Die Kieselschaligen Bacillaria oder 
Diatomeen, p. 82. t.25.f.7. KH. paradoxum, Kutz. Synop. Diatom. 
in Linnea 18338, p. 589. f. 73; Die Kies. t. 22. f. 1. Monema 
prostratum, Berk. Br. Alg. p. 15. t. 4. f.3. (1832)! Schizonema 
prostratum, Grev. in Hook. Br. Fl. vol. ii. p. 414; Harv. Br. Alg. 
p. 214. Gloionema paradoxum, Ehr. Inf. p. 237 (not of Agardh 
nor Kiitzing); Portlock in Microscop. Journ. vol. ii. p. 6. pl. 3. 
fey. 
In freshwater rivulets, outlets of ponds, &c. near King’s Cliffe, 
Northamptonshire, Rev. M. J. Berkeley ; Farnham, Surrey, Mr. W. 
Reeves; Brambletye, Sussex, and ‘‘ abundant in the rivulet which 
parts Kent and Sussex between Bodiham and Sandhurst,” Mr. Jenner; 
near Bristol, Mr. Thwaites. Ufracombe, Devonshire, J. &.; ‘* Lough 
Erne, Ireland, Capt. Portlock.” 
This plant forms small tufts, which not unfrequently are so 
