648 MB. W. JOSHUA ON BUBMESE DESMIDIE.2B. 



base and widening upwards ; in side view, cells globose (width 

 of isthmus about half the transverse diameter) ; angle at point 

 of juncture forming a wide notch. Length 51 \i ; breadth 

 without spines 40 \i. 



C. SUBTUMIDUM, Nordst., 0. PLATYDESMIUM, Nordst. 



C. incisum, n. sp. (Plate XXIV. figs. 28 & 29.) 



C. mediocre : cellulis plus 1^-plo longis quam latis : constric- 

 tione angustata, lineari : semicellulis subquadratis ; basi recta : 

 angulis apicalibus rotundatis, apice truncato, late depresso ; 

 membrano interiore minute granulato : isthmo angusto. Longit. 

 38^, latit. 26 fi, crassit. 19 /x : isthmi latit. 18 ft. 



Medium size ; cells rather more than 1| times as long as wide ; 

 constriction narrow, linear ; semicells subquadrate ; base straight; 

 apical angles rounded ; apex truncate, with wide depression ; 

 inner membrane minutely granulate ; isthmus narrow. Nearest 

 some of the forms of C. Meneghinii, Breb. Length 38 fx ; 

 breadth 26 /z ; thickness 19 /i ; width of isthmus 1 8 yu. 



C. annulatum, Naeg., f . Except in shape of granules, identical 

 with C. elegantissimum, Lundell. 



C. PA.CHYDEEMUM, Lutld. 



C. PACHTDEBMUM, /3. MINUS, Nordst. 



C. GEMINATUM, Lund. 



C. Bailetti, Wolle. 

 C. Pobtianum, Arch. 

 C. PYGMiEUM, Arch. 

 C. TETBAGonum, Naeg., Arch. 

 C. contbactum, Kirschner. 

 C. subbotundum, Delponte. 

 C. Bicabdia, Beinsch. 



C. undulatum, Corda, y. minutum, Wittr., var. obnatuat, 

 Schacer. 



C. depbessum, Naeg. 



C. QUADBATUM, JRalfs, f. 



C. pardalts, Cohn, f. minob, n. var. (Plate XXIV. fig. 20.) 



C. inobnatum, n. sp. (Plate XXIV. figs. 26 & 27.) 



C. mediocre, nonnihil duplo longius quam latum, fere cylindri- 



cum, apice leviter truncato : lateribus late rotundatis ; centro 



leviter constricto ; angulo latiore : semicellulis a latere conspectis 



ellipsoideis ; membrano crenato ; verrucis indistinctis, nullis in 



