EUASTRUM. / 



latum Breb." ; "var. majus Rabenh."), but which is not a 

 true variety. Frequently one semicell is typical and the 

 other in possession of this lateral protuberance. Such is the 

 example we have figured on PL XXXIII, fio\ 4. Consult 

 also, West, ' Alg. K Wales/ 1890, p. 287, t. 6, fig. 33. 



The Desmid to which Bennett gave the name " E. crasso- 

 Jnimeroxum n. var." is a very badly drawn specimen of 

 E. crassum, in which the interlobular incisions were somewhat 

 open. Bennett's idea that it was a hybrid was a mere 

 supposition; he did not even examine the nature of its pro- 

 tuberances or obtain its other views. 



Var. scrobiculatum Lund. (PI. XXXIII, figs. 7, 8.) 



E nostrum crassum var. scrobiculatum Lund. Desrn. Suec. 1871, p. 18, t. 2, 

 f. 1 ; Nordst. Norges Desni. 1873, p. 8 ; Be Toni, Syll. Alg. 1889, p. 1088 ; 

 West, Alg. W. Ireland, 1892, p. J 36 ; West & G. S. West, Some N. Ainer. 

 Desni. 1896, p. 242, c. fig. xylogr. ; Alg. S. England, 1897, p. 483 ; Alg. 

 N. Ireland, 1902, p. 27. 



Cells usually smaller than in the type ; lateral mar- 

 gins of semicells not so hollowed, often straight ; in 

 the centre of the semicells (in the neighbourhood of 



V o 



the two small tumours) with 1-6 large scrobiculations, 

 variously disposed ; side view of semicells with more 

 yentricose lateral margins, considerably attenuated 

 towards the apex ; vertical view rather more rectan- 

 gular-oblong than in the type. 



Length 134-169 /x; breadth 65-88 p. ; breadth of 

 isthmus 18-26 p ; thickness 51-65 JJL. 



ENGLAND. Xew Forest, Hants ! 



SCOTLAND. Skye, Inverness ! Harris, Lewis, 

 X. Uist, and Benbecula, Outer Hebrides ! 



WALES. Moel Siabocl, bog above Capel Curig, bog- 

 between Grlyder Fach and Llugwy, Carnarvonshire ! 



IRELAND. Xear G-weedore, near Loughs Grlentornan 

 and Magrath, Donegal ! Cromagloun, Kerry ! 



Geogr. Distribution. Germany. Norway. Sweden. 

 Denmark. Poland. Faeroes. United States. West 

 Indies. 



This is a very characteristic variety of rare occurrence. 

 The scrobiculations in the centre of the semicells, which are 

 the largest marks of that type in any Desmid , vary much in 



