252 



shorter not ramified part, then a single lateral branch occurs (lig. 1 c), 

 then again a longer not ramified part; the topmost cells in the 

 apex of the plant were dead or more or less disorganized. 



The plant here figured is nearly 3 cm. long. The breadth 

 varies, with an average of about 28 fi\ the length of the cells is 

 ten times the breadth. 



313. Ægagropila Martensii Menegh. Plate X, fig. 1. 



Unfortunately I have only had dried material for examination ; 

 it was collected bj^ Ostenfeld in Sandsvatn on S an do where it 

 was floating about in the water. The size of the single colonies 

 [Cænohia cfr. K j e 1 1 m a n ^) varies from that of a pea to that of a 

 hazel-nut. The single larger specimens which occur occasionally 

 are no doubt made up by the pressing together during desiccation 

 of smaller specimens, at any rate they are very easily separated 

 and Ostenfeld also tells me that he does not remember having seen 

 any larger than a hazel-nut. 



At the time of gathering the single cænohia were doubtless 

 nearly spherical, though somewhat irregular in form, some of the 

 apices of the branches having here and there protruded beyond 

 others. The filaments of cells are somewhat rigid and loosely 

 connected so that the whole cænobium has a less compact appear- 

 ance. The colour of the dried plant is a dark dingy olive green, 

 and according to Ostenfeld that of the living plant was the same. 

 The cells were so opaque that it was necessary to soak the mate- 

 rial in potassium hydrate in order to render it transparent for mi- 

 croscopic examination. 



When placed under a microscope and slightly magnified the 

 cænobium presents the following features: — from a certain point 

 on the cænobium — a point sometimes in the middle and some- 

 times nearer the margin — numerous copiously ramified branches 

 or individuals radiate; in younger piants these must be regarded 

 as branches belonging to the same plant, but in older specimens 

 they occur as independent individuals, the more or less copiously 

 ramified branches having become separated through the death of 

 the older cells in the middle of the cænobium. All these indivi- 

 duals are kept together partly by the entangling of the branclies, 

 and partly and mainly by means of the rhizoid-like branches, which 



^ F. R. Kjellman: Zur Organographie und Systematik der Ægagropilen in 

 Nova Acta Reg. Soc. Ups. Ser. 111. 1898. 



