66 BRITISH DESMIDIACE^. 



Cells rather smaller than in the type; polar lobe 

 subrectangular, angles rounded, apex faintly retuse ; 

 lateral lobes retuse, scarcely bilobulate, angles rounded ; 

 interlobular incisions widely open, subrectangular ; pro- 

 tuberances within the lateral lobes much reduced, 

 scarcely evident in the vertical view ; vertical view of 

 polar lobe rectangular with straight sides. 



Length 80-89 p. ; breadth 70-86 //, ; breadth of 

 isthmus 18*5-22 JJL ; breadth of polar lobe 29-36 p ; 

 thickness 36-42 p. 



SCOTLAND. Plankton of Lochs Tay and Achray, 

 Perth ! Plankton of Loch Ruar, Sutherland ! (J. 

 Murray). General in the plankton in Inverness, Lewis, 

 and Harris, Outer Hebrides ! Plankton of Xeugles 



* o 



Water, and of Loch Beosetter, Bressay, Shetlands ! 



IKELAND.- -Lough G-artan, Donegal ! 



Geogr. Distribution. Finmark in Norway. N". 

 Russia. United States. Uruguay. Argentina. 



Var. coarctatum Delp. (PL XL, fig. 4.) 



E. verrucosum var. coarctatum Delp. Desm. snbalp. 1873, p. 95, t. 6, f . 16 ; 

 Racib. Nonn. Desm. Polon. 1885, p. 94, t. 13, f. 11 ; De Toni, Syll. Alg. 

 1889, p. 1067 ; West, Alg. W. Ireland, 1892, p. 136 (forma). 



Cells slightly smaller than in the type, sinus gene- 

 rally more closed ; polar lobe prominent, exserted, apex 

 only slightly retuse ; lateral lobes scarcely bilobulate, 

 widely retuse. 



Length 92*5-97 p,; breadth 85-87 //, ; breadth of 

 polar lobe 31-35 p.; breadth of isthmus 20-23 p. 



IRELAND.- -Derryclare Lough, Galway ! 



Geogr. Distribution. Galicia in Austria. Poland. 

 Italy. 



A form of this variety is figured in which the upper angles 

 of the lateral lobes are much reduced, and the polar lobe 

 appears still more prominent ; length 90 /UL ; breadth 76 JJL ; 

 breadth of polar lobe 32*5 /u; breadth of isthmus 21 /u (PL XL, 

 fig. 5). This form was originally figured in West, ( Alg. W. 

 Ireland/ 1892, t. 20, f. 11. 



