ME. W. JOSHUA ON BUEMESE DES31IDIE.E. G53 



no central inflation ; apices slightly dilated on both sides ; beyond 

 suddenly attenuated ; central part with 3 transverse striae ; mem- 

 brane thick, yellowish brown, marked longitudinally with 18-20 

 striae. It comes near to C. lagoense, Nordst., but is of a more 

 slender habit, and has the incrassate apical lobes. Length 187 fi ; 

 width 20 /ii ; width at inflation 13 /*. 



16. Penium, Breb. 

 P. delicatulum, n. sp. (Plate XXV. figs. 9 & 10.) 

 P. parvum, subcylindricum, duplo et ultra longius quam latum, 

 utroque latere medii leviter emarginatum : semicellulis apice 

 conicis, membrauo interiore valde atteuuato, minute regulariter 

 punctato. Longit. 63 fi, latit. 26 fi. 



Small, subcylindrical, rather more than twice as long as wide ; 

 on both sides of middle slightly emarginate ; semicells conical at 

 end ; much attenuated inner membrane minutely and regularly 

 punctate. Length 63 fi ; breadth 26 /x. 



P. MAEGAEITIFERUM, Ehrerib. 



P. spibostbiolatum, Barker. 



P. digitus, Breb. 



P. lamellosum, Breb. 



P. (Cylindbocystis) Bbebissonii, Menegh. 



P. closteeioides, Ralfs. 



P. minutissihum, Nordst. 



P. navicula, Breb. 



EXPLANATION OF THE PLATES. 

 Plate XXII. 

 Figs. 1 & 2. Sph&rozosma pulchrum, Bailey, /3. trilobum, n. var. : 1, filament, 

 X 400 ; 2, end of filament seen crossways. 



3. Desmidium quadratum, Nordst.; conjugated zygospores, x400. 



4, 5, & 6. Closteritim Bacillum, n. sp., X200. 



7, 8, & 9. Closterium nematodes, n. sp. : fig. 7, X300 ; and 8 & 9, X400. 

 10 & 11. Micrasterias Crux-melitensis (Ehrenb.), Kalfs, var. n. f., X300. 



12. Micrasterias Lux, n. sp., X300. 



13. Micrasterias apicidata, Menegh., n. f. 



14. Micrasterias euastroides, n. sp., x 300. 



Plate XXIII. 

 Figs. 1 & 2. Euastrum serra/um, n. sp. : 1, cell, XGOO; 2, side view of same, 

 X300. 



