225 



Fam. XL HYDRODICTYONEiE. 



21. HYDRODICTYON Roth: 



Char, Cells arranged in the form of a pe7ita//on, an aggre- 

 gation of a number of these pentagonal meshes, going to 

 form an entire plant. Zoospores numerous in each cell, 

 and uniting together before the absorption of the parent 

 cell membrane. 

 Derivation. From vhcop, water, and Siktvov, a net. 



1. Hydrodictyon utriculatum Both. 



Plate LVIII. 



Char. Same as those of the genus. 



Harv. in Hook. Br. Fl. vol. ii. p. 359. Conf. reticulata, 

 E. B. t. 1687. ; DiUw. t. 97.; Vanch. Conf. cl'Ean douce; 

 Harv. Manual, p. 140. 



Hab. In ditches and pools in the midland and southern 



counties of England. In a pond in the Botanic Garden 



at Cambridge, where it has existed for many years: 



Rev. Prof. Hensloio. Not found in Scotland or Ireland 



hitherto. 



Hydrodictyon utriculatum is one of the most remarkable 



of the freshwater AlgcB. The credit of the discovery of the 



singular reproduction of this species is due entirely to 



Vaucher, whose account of it is so clear and well expressed 



that I cannot do better than translate his remarks: — Each of 



the fine filets (cells) which form the pentagon begins to swell 



a little, principally at the extremities, then it is separated 



from the others not by a rupture, properly so called, but by 



