614 Cushman: Desmids from New England 





Arthrodesmus Incus longispinus Eichl. & Racib. 



Length with spines 46 fi, without 26 fi ; breadth with spines 

 34/1, without 14/i; length of spines 15/*; isthmus 5//. Occa- 

 sional, St. Anthony. 



STAURASTRUM Meyen. 1829 



55. Staurastrum aristiferum Ralfs. 



Length 40 fi\ breadth without spines 68 ft; isthmus 9 /i. 

 Occasional, St. Anthony. 



6. Staurastrum dubium West. 



Length 28 jut; breadth 22 fi; isthmus 10 ji. Very common, 

 Rose au Rue. 



57. Staurastrum longispinum bidentatum (Wittr.) Cushman. 



Length 90 fi ; breadth with spines 108 //, without 83 fx ; 



1 



isthmus 40//. Rare, St. Anthony. 



58. Staurastrum arcuatum Nordst 



Breadth with processes 45-50 fx ; isthmus 8.5 fx. Occasional, 

 St. Anthony. 



59. Staurastrum nanum Wolle. 



Length 25 fi ; breadth with spines 31 fx } without 22 fx ; isthmus 

 8 ft. Common, Rose au Rue. 



60. Staurastrum Johnsonii W. & G. S. West. 



Length 56/^; breadth 84^; isthmus 9.5 fx. Occasional, St. 

 Anthony. 



61. Staurastrum gracile Ralfs. 



Length with processes 58/7, without 15//; isthmus 8 //. 

 Not common, St. Anthony. 



62. Staurastrum crenulatum (Nag.) Delp. 



Breadth 25-37 ft; isthmus 9 p. Rare, Rose au Rue. Fre- 

 quent, St. Anthony. 



63. Staurastrum macrocerum Wolle. 



Length 48//; breadth with processes 100 fx ; without 28//; 

 isthmus 18/i. Common, St. Anthony. 



64. Staurastrum echinatum Breb. 



~ X ~TJ (-J «»v.uuiu Willi Opil 



out 37 t u ; isthmus 16 ft. Occasional, St. Anthony. 



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