Mr. Hassall on the Branched Freshwater Conferva. 361 



the branched Confervae does not appear to have been noticed, 

 so far as I am aware, by any other observer save Vaucher, and 

 by him only in the Batrachiosperms, and yet it is of frequent 

 occurrence, and affords a character whereby often species may 

 be distinguished from each other, although at the same time 

 it changes the ordinary appearance of species so much as to 

 lead sometimes to the description of specimens so altered as 

 distinct species ; and this has doubtless been the case with 

 Conferva fracta of the ' Flora Danica,' which I take to be 

 nothing more than C. crispata in a state of reproduction. 



It is then by means of the small granules to which refer- 

 ence has been made, which, although they have undergone a 

 considerable increase in size, are not one-twentieth part so 

 large as the true spores of the Conjugates and of the Vesicula- 

 sperms, that the branched Confervas are perpetuated; and 

 hence we see the necessity and wisdom of the law of lateral 

 growth to these Confervae, which otherwise would be placed 

 amongst the most minute objects of creation. 



And it is, therefore, amongst the branched freshwater Con- 

 fervae that we are principally to look for members of the once 

 apparently important class of Zoospores. If there be such 

 things, and it can scarcely be doubted but there are, it is here 

 that they will chiefly be found. I have myself tried to detect 

 motion of the reproductive granules, (which motion, by the 

 way, is no conclusive proof of animality,) and once only in Con- 

 ferva glomerata did I observe any motion of bodies within the 

 cells ; and these might possibly have been small animalculae 

 which had effected an entrance through the aperture said to 

 be provided for the escape of the zoospores, which aperture 

 I have observed only in Conferva glomerata, in which it in- 

 variably occupies a determinate situation at one side of the 

 upper extremity of each cell ; a fact in itself so strong, as in my 

 opinion at once to throw discredit upon the explanation of 

 Agardh as to the manner of the formation of the aperture, 

 viz. by the reiterated pulsations or knocking of the confined 

 zoospores against the sides of the walls of the cells. 



The freshwater species of the branched Confervae appear to 

 me to resolve themselves into the following genera, the whole 

 of which, including the genus Bulbochcete, appear to form an 

 exceedingly natural group, which I propose to designate Mi- 

 crosperms. First, into the genus Bulbochaete, which may be 

 thus defined : — 



Genus Bulboch;Ete. 



Filaments attached, of equal diameter, branched ; cells trun- 

 cate, setigerous, the setae being rigid, elongated and bulbous 

 Ann. $ Mag. N. Hist. Vol. xi. 2 B 



