296 
Transactions of the Society. 
S. sexcostatum Breb. P., S. 
S. margaritaceum Meneg. Do., S., F., B. 
A form which showed short spines irregularly disposed at the 
apices is figured from Capel Curig. Fig. 32. 
var. coRONULATUM nov. var. Fig. 3. 
Yar. cumannulo granulorum parvorum ad apices trun- 
cates semicellularum. 
This has the apices of the semicells truncate and bordered by a 
circle of small granules. P. 
*S. iotanimi Wolle. C. Fig. 9. 
This tiny species may easily escape observation. Its arms are 
similar to those of St. tetracerum Kalfs, but much finer and more 
delicate, the end view being also triradiate. Its form in front view is 
not unlike those of St. O'Mearii Arch, and St. ^pterosporum Lund., 
but it is smaller, and has arms and not spines. 
Class Multinucleat^. 
Order Siphone2e (Coeloblastae). 
Genus Vaucheria DO. 
V. sessilis Vauch. Penmaenmawr. 
Class CcENOBIEiE. 
Order Pandorineai:. 
Genus Payidorina Ehrb. 
P. morum Ehrb. B., 0. 
Order Pediastre^. 
Genus Pediastrum Meyen. 
P. angulosum Ehrb. C. 
P. Boryanum Turp. A., Do., Llandudno, Bodorgan. 
var. granulatum Ktz. A., 0. 
P. hidentulwn A. Braun. C. 
P. constrictum Hass. A. 
P. pertusum litz. A. 
P. Ehrenbergii A. Braun. A., C. 
Order Sorastre^. 
Genus Coelastrum. 
C. microsporum (Nag.) Braun. 0. 
