VII. OBSERVATIONS ON DICTYOSPH^RIA. 



CAROLINE M. CROSBY. 



NOMENCLATURE AND CLASSIFICATION. 



The genus Dictyos-phcBria was founded by Decaisne, Valonia 

 favulosa Ag. being chosen as the type. In further investiga- 

 tions by Harvey, Agardh, Kiitzing and Murray, this systematic 

 position has been accepted by all, near Valonia and Anadyomene. 



The present investigations have been confined to the single 

 species Dictyosphceria favulosa^ and to material collected in the 

 Hawaiian Islands during the summer of 1900. 



These notes will not attempt to discuss the classification which 

 has been so firmly established, but will merely add some details 

 of structure not noticed at length by Murray, and some possible 

 explanations of certain disputed points. 



COLLECTION AND PRESERVATION OF MATERIAL. 



The material was collected in the following portions of the 

 Hawaiian Islands, May-August, 1900: 



1. Kapaa, Island of Kauai, most northern point. 



2. Waianae, Island of Oahu, most southern point. 



In all cases the material was collected at or near low tide, in 

 shallow water. 



The material used was preserved 



1. In 70 per cent, alcohol solution. 



2. In 4 per cent, formaline solution. 

 Investigations were made chiefly on formaline material. 



METHODS OF PREPARATION. 



i. The material prepared with alcohol was allowed to stand 

 twenty minutes or so in gum-arabic solution and then trans- 

 ferred to gum-arabic solution on the freezing chamber. As 

 this medium necessitated transference to glycerine jelly as a 

 mounting medium, the tissue proved too delicate for successful 

 study. 



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