THE GREEN ALGAE OF NORTH AMERICA 145 



4. Spines very slender, all about 5 /j. long. 4. T. aciculifera. 



5. Ridges intersecting, enclosing angular areas. 5. T. relicularis. 



5. Ridges parallel or concentric. 6. 



6. Membrane one-sixth cell diain. 7. T. obtusa. 



6. Membrane one-third cell diam. 6. T. arguta. 



1. T. GRANULATA (Reinsch) Hansgirg, 1888, p. 128; 

 P. B.-A., No. 761. Acanthococcus granulatus Reinsch, 1886, p. 

 239, PI. XI, figs. 3, 4, and 7. Cells solitary or united in small 

 families, globose, 18-22 /A diam., membrane one-fifth to one-sixth 

 cell diam., covered with rather distant, bluntish, warty projec- 

 tions. Mass. Europe, So. America. 



2. T. ASPERA (Reinsch) Hansgirg, 1888, p. 128; Acantho- 

 coccus asper Reinsch, 1886, p. 239, PI. XI, fig. 2. Cells soli- 

 tary, globose, 14-17 ^ diam. ; membrane one-eighth to one-ninth 

 cell diam., densely covered with somewhat acute, warty projec- 

 tions. Dominica. Etirope. 



3. T. HIRTA (L,agerh.) Hansgirg, 1888, p. 128"; Acantho- 

 coccus hirtus Lagerheim, 1882, p. 78, PI. Ill, figs. 38 and 39; 

 Wittr. and Nordst., Alg. Exsicc., No. 446. Cells solitary or 

 united in small families, globose, 22-32 //, diam., membrane one- 

 eighth to one-ninth cell diam., with pyramidal spines of unequal 

 length, one-fourth to one-fifth the cell diam. Fig. 32. Green- 

 land. Europe. 



4. T. ACICULIFERA (Lagerh.) Hansgirg, 1888, p. 129; 

 Acanthococcus aciculiferus Reinsch, 1886, p. 241, PI. XI, fig. i. 

 Cells solitary or united in small families, globose, subglobose or 

 ovoid, 15-30 //. diam. ; densely coated with very numerous 

 slender spines, up to 5 /x, long. Mass. Europe. 



5. T. RETICULARIS (Reinsch) Hansgirg, 1888, p. 129; P. 

 B.-A., No. 1514; Acanthococcus reticularis Reinsch, 1886, p. 241, 

 PI. XI, figs. 12 and 14 ; including T. sporoides (Reinsch) Hans- 

 girg, Acanthococcus sporoides Reinsch, 1886, p. 242, PI. XII, fig. 

 24 ; and T. Reinschii Hansgirg, Acanthococcus sp., Reinsch, 1886, 

 p. 242, PI. XI, fig. 13. Cells solitary or united in 5-8-celled 

 families; globose or subglobose, 15-37 n diam., membrane one- 

 eighth to one-ninth cell diam., with ridgy or wavy prominences, 

 running in various directions, and intersecting to form 24-70 

 angular areas. Fig. 32. Mass., 111. Europe. 



T. sporoides, according to description and figures, differs only 

 in not forming families, and in having 60-70 areas formed by 

 the more numerous ridges, while T. reticularis has 24-36. T. 

 Reinschii shows no difference whatever in the description, and 



