88 BRITISH 



Var. simplex West. (PI. XLIII, fig. 3.) 



If. Jenneri var. simplex West, Alg. N. Wales, 1890, p. 287, t. 6, f. 34 ; Alg. 



W. Ireland, 1892, p. 135 ; West and GK S. West, Alg. S. England, 1897, 



p. 48-4 ; Alg. N. Ireland, 1902, p. 30. 

 M. Jenneri forma Brasiliensis Borg. Desm. Brasil. 1890, p. 32, t. 3, f. 13. 



Cells with tlie lateral lobes entire and slightly retuse, 

 polar lobe narrower and more cuneate; cell- wall smooth 

 or punctate. 



Length 127-150 /*,; breadth 95-100 p.; breadth of 

 polar lobe 53-56 /A; breadth of isthmus 25-34 p.. 



ENGLAND. Near Stickle Tarn, Westmoreland ! New 

 Forest, Hants ! 



WALES.- -Dolgelly, Merioneth ! 



SCOTLAND. Moidart, Inverness ! 



IRELAND. (Plenties, Donegal ! Ballynahinch, Gal- 

 way ! Lough Fea, Londonderry ! 



Geogr. Distribution. Brazil. 



6. Micrasterias conferta Lund. 

 (PI. XLIII, figs. 4-8.) 



Micrasterias conferta Lund. Desm. Suec. 1871, p. 14, t. 1, f. 5 ; Wolle, 

 Desm. U.S. 1884, p. 114, t. 53, f. 12, 13; Cooke, Brit. Desm. 1886, p. 59, 

 t. 28, f. 2 ; Roy & Biss. Scott. Desm. 1893, p. 173 ; West & G. S. West, 

 Scott. Freshw. Plankton, I, 1903, p. 525. 



M. granulata Wood, Freshw. Alg. N. Amer. 1874, p. 146, t. 21, f. 16. 



Helierella conferta Kuntze, Revis. gen. plant. 1891, p. 898. 



Cells somewhat small, broadly elliptic, deeply con- 

 stricted, sinus narrowly linear (often entirely closed by 

 the overlapping of the basal angles of the semicells) ; 

 semicells five-lobed, with all the lobes and lobules 

 closely approximated, the interlobular incisions being 

 narrowly linear and not very deep; polar lobe sub- 

 cuneate, dilated from a somewhat narrow base, lateral 

 margins concave, apex convex but retuse in the middle, 

 with two minute papillae on the apical margin near 

 each of the slightly-obtuse angles, often with a pair of 

 small teeth on each side of the median hollow ; lateral 

 lobes about equal in breadth, each divided by a shallow 

 incision into two lobules, lobules again divided, the four 

 ultimate divisions being equal in size and retuse-emar- 



