EUASTKUM. 47 



quadrate, ornamented with 6-8 acute granules (3-4 

 marginal) ; semicells with a triverrucose protuberance 

 in the centre above the isthmus, a large rounded 

 granule on each side of the apical incision, and often 

 a small granule at each angle of the apical incision. 

 Side view of semicell ovate-oblong, with an emarginate 

 protuberance at each side near the base, and a rounded 

 granule at each side near the apex, apex rounded and 

 furnished with a spine. Vertical view oblong, with 

 rounded denticulate poles, and an emarginate protu- 

 berance in the middle on each side. 



Zyo-ospore unknown. 



Length 37-40 M ; breadth 28-33 ,u; breadth of 

 isthmus 7-8 f.i ; thickness 19-20 n. 



EXGLAXP. Bowness, Westmoreland ! Riccall Com- 

 mon, E. Yorks ! Xew Forest, Hants ! Tremethick ]\loor, 

 'Cornwall ! 



SCOTLAND. Sutherland !, Eoss, Aberdeen, Kincar- 

 dine, Forfar, Perth, Argyll (Roy $ Bisxeit). Harris and 

 Lewis, Outer Hebrides ! 



IRELAND. Duno-loe, Loughs G-artan and Machugh, 



o 



Sproule's Lough, Donegal ! Lough Derryclare and 

 Oughterard, Gralway ! 



. distribution. France. 



Brebisson/s figure of E. pulcliellum is a very poor one and 

 is inaccurate in its details. We find the species scarce but 

 widely distributed in the British Islands. 



Perhaps the figure given by Wolle, f Desm. U. S. ; t. 27, f. 9, 

 of E. rostraium belongs to this species. 



Var. retusum nov. var. (PI. LXIV, fig. 17.) 



Lateral lobes less protuberant, broader, and slightly 

 retuse on their outer margin, with the upper angles 

 emarginate ; polar lobe with a convex apex and with 

 the median notch widely open. 



Length 40 p,; breadth 26 ^', breadth of isthmus 



f f 

 ro p.. 



EXGLAXD. Bowness, Westmoreland ! 



