COSMARIUM. 65 



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

 brane distinctly punctate. 

 Diameter 54 //. ; length 66 //. 

 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 Nord- 

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

 granuliferum reminds one of C. cymatopleurum, Nord., C. de 

 Notarisii, (Witt.), l^ord., and C. capense, !N"ord., but it is 

 distinct. 



. 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. 



. GLOBOSUM, Buluh. Plate LX, figs. 14-17. 



Cells small, light green, bicocciforin, 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 ^ ; length 25-33 /*. 



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. 



C. PERFORATUM, Lund. Pl,ate XL VI II, 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 flattened 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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