PLErnOTVENIlTM. 207 



somewhat tumid, or the lateral maro-ins may be parallel. 

 Tliere is one basal inflation with usually another smaller 

 undulation just above it. The apical tubercles ai-c never 

 absent, but in rare instances they may be much reduced. 



A curious form of this species is ii^-ured on PI. XXX, fio-. 2. 

 The cells are larger than usual and there is a lar^v inihitimi 

 on each semicell above tlio basal inflation. The specimen \vas 

 From Capel Ctiri^ 1 , X. Wales ; length 1- !"> // ; breadth above 

 basal inflation (max. breadth) o7- !()/<; breadth of apices 

 '24 ft. We have noticed the same form from the plankton of 

 Locli Fadaghoda, Lewis, Outer Hebrides. 



Var. granulatum Ealfs. 



'i'iiii var. granulatum Ealfs, Brit. Desm. 1848, p. ir>7, 

 t. 3.3, f. 4 ; West, Ali?. N. Wales, 1890, p. 284 ; Eoy & Biss. Scott. Desm. 

 1894, p. 241 ; West \ (>. S. West, Alga-fl. Yorks. 1900, p. :>s. 



A variety with the cell-wall distinctly and coarsely 

 granulate. 



Length 350 /A; breadth at base of semicells 33^,; 

 breadth at apices 20 p. 



ENOLAND. W. and N. Yorks! Sussex (7.W/V). 

 Hants (Iin,j). Cornwall ! (Unlfr). 



WALES -Capel Cnrig, Carnarvonshire ! 



SCOTLAND. Aberdeen (Iloij cj 1 Ili^cft). Perth ! 

 . Distribution. Bohemia in Austria. 



Var. elongatum West. (PI. XXX, fig. 3.) 



Docidivm Ehi'?Hl>ci-<ji! var. elongatum West, Alg 1 . N. Wales, IS'.K), p. 2M. 

 Pli< a ,<>/. T, i 'ii<, a Ehrenbergii var. elongnfi'm Wr.--1. Al" 1 . W. Ireland, IS'.H'. 

 p. 119. 



Cells narrow and much elongated, about 25 times 

 longer than the diameter. 



Length 525-575 ^ ; breadth at base of semicells i23- 

 w 2(>jLt, in middle 21-22*5 /x, at a])ices 17-19/z. 



\\'.VLES. Capel Curig, Carnarvonshire! 



IRELAND. Clifdeu, Galway ! 



Var. undulatum Schaarschm. 



Pleurotcenivm. Ehrettlicrgii var. nml nJntinu Schaarschm. Magyar. Desm. 

 iss::. p. L'TS, t, 1, f. 2l' ; Schmidle, Al^. aus Sumalra. ]su:>. p. I'.iio with 

 ti- : West &G-. S. West. Freslnv. Al-. Ceyl.m, 1<K>2, p. 145. 



