62 Algae. 



kommt im Gebiete des Mittelmeeres sehr selten und spärlich vor; 

 sie wurde zum ersten Male bei Lesina (Dalmatien) im Adriati- 

 schen Meere von Botteri gesammelt und als neue Art von 

 Zanardini aufgestellt; dann haben andere Autoren Galaxaura adriatica 

 in entfernten Orten gefunden, z. B. bei Miramar (Hauck), Neapel 

 (Berthold), Tripolis (De Toni und Levi) und A 1 b i s so 1 a m a r in a 

 <Piccone), J. B. de Toni (Modena). 



Crosby, Caroline M, Observations on Dlctyosphaeria. 

 (Minnesota Botanical Studies. Vol. III. March 21, 1903. 

 p. ()1— 70. pl. 15.) 



Material from the Hawaiian Islands was studied by the 

 iollowing method. Formaline material was cut by means of 

 freezing and after various trials it was found that Anilinewater 

 safranine for four minutes was the most satisfactory stain 

 showing well the structure of the cell wall etc. Gentian violet 

 differentiated pyrenoid centers clearly, but was too strong for 

 all other structures. Acid fuchsin three hours proved best for 

 the nuclei. Formalin was prefered for mounting. 



The plant body of Dlctyosphaeria is compared to a primi- 

 tive irregulär sessile branched System, homologous to the elon- 

 gated branched System of Stnivea. On account of this structure 

 and the presence of well developed rhizoids it is considered to 

 be a low type among the Valonlaceae. 



The cell walls of this alga are fibrillated in appearance, due 

 to a varying number of membrane like layers. Sphaerocrystals 

 were not found. The development of the strengthenings of the 

 inner cell begins with the invagination of an increasing number 

 of stratifications, the inner forming the external wall of the 

 needle. These needles are considered to be allied to the streng- 

 thening structures in Caiilerpa, but are subsidiary to the haptera. 

 These latter are formed by the evagination of about one third 

 of the cellwall similar to the invagination in the formation of 

 the internal structures. 



This evagination continues until a surface is reached, when 

 the Stimulus received causes a dichotomous lobing and the 

 hollow formed between the concave center of this lobe and the 

 contact wall causes sufficient suction to produce adhesion. 

 Rhizoids are developed from the ventral surface of the thallus 

 and correspond to normal plant cells, being little differentiated. 

 To strengthen their function as primitive holdfasts haptera are 

 formed from their outer edges. 



An investigation of the cell Contents showed that there was 

 a large amount of watery colorless cell sap, with the periphery 

 lined by polygonal, plate like chromatophores, which are easily 

 detached from the cell wall. A single pyrenoid is present in 

 each chromatophore and from one to eight or more starch 

 grains are present. Moore. 



