COSMAEIUM. 65 



in vertical view oval ; in lateral view broadly oval. Mem- 

 brane distinctly punctate. 

 Diameter 54 pi. ; length 66 yu. 

 Tewksbury, Massachusetts. 



The author of the present name for a Cosmarium, G. von 

 Lagerheim, of Stockholm, Sweden, finds that we have du- 

 plicated the name pseudogranatum, previously used by Word- 

 stedt, hence re-names the form as above. The new variety 

 granuliferum reminds one of C. cymatopleunim, Nord., G. de 

 Notwi-isii, (Witt.), Nord., and G. capense, ISTord., but it is 

 distinct. 



•C. MONiLiFORME, Ealfs. Plate XVIII, figs. 16, 17, 18, 19. 



Cells twice as long as wide ; semi-cells spherical, united by 

 a narrow isthmus ; four semi-cells often in series ; cell mem- 

 brane smooth. 



Diameter 16-24 yu. 



Frequent in ponds, Pennsylvania, New Jersey, Massachu- 

 setts, Florida, etc. Fig. 18 represents a peculiarity noticed 

 now and then, that in multiplying by division, (Introduction 

 p. 17), the new daughter semi-cells are larger than those of 

 the mother cell ; if this is not always the case such are fre- 

 quently found. 



C GLOBOSUM, Bulnh. Plate LX, figs. 14-17. 



Cells small, light green, bicoceiform, scarcely compressed, 

 nearly one -third longer than wide, very slightly constricted, 

 sinus acute ; semi-cells circular, exclusive of the confluent 

 bases, entire, cytioderm smooth or finely punctate. 

 Diameter 20-24 jn. ; length 25-33 yu. 



Not infrequent in ponds intermingled with other forms. 

 Plate XV, fig. 20, represents a variety which stands between 

 this species and moniliforme. 

 Diameter about 20 ,". 

 Pennsylvania, New Jersey, Massachusetts. 



€. PEEFOEATUM, Lund. Plate XLVIII, fig. 32. 



Somewhat circular, slightly longer than broad, moderately 

 constricted in the middle, sinus acute angled, enlarged out- 

 wardly, rarely linear ; semi-cells sub-semi-circular, back 

 high convex, with the middle slightly fiattened or rarely 

 slightly retuse ; end view broadly elliptical ; lateral view 

 circular with base broadly truncate. Membrane distinctly 

 but sparsely punctate, often with larger granules arranged 



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