MESOCARPUS. 167 



var. /3. Sporangia circular. 



Mougeotia scalaris Hassall, in Annals and Mag. of Nat. 

 Hist. vol. x. p. 45. pi. 7. fig. 7. Zygnema ordinarium ? 

 Berkeley's Gleanings. Sphcerocarpus scalaris var., An- 

 nals of Nat. Hist. vol. xii. p. 186. pi. 7. fig. 8. 



Hab. England ; common, var. /3, Crowborough Warren : 

 Mr. Jenner. 



This is one of the commonest as well as most distinct 

 species of the genus. I have encountered it repeatedly myself, 

 and have also received it from Mr. Jenner. Z. ordinarium 

 Berkeley is quoted as a synonyme with considerable doubt ; 

 but if that species be not the one above described, I am at 

 a loss to which of the other species of the genus described in 

 this paper it ought to be referred. The filaments in Meso- 

 carpus scalaris, as well as in the majority of the other species 

 of genus, are of a yellowish green, owing to the greater 

 impurity of the water in which they dwelt. 



Plate XLII. fig. 2. represents what I shall here describe 

 as a variety of this species. The filaments are of the same 

 diameter, but the sporangia, instead of being oval, are spherical. 

 It is very probable that this is really a distinct species ; but 

 having seen it but once, I hesitate so to regard it. 



2. MESOCARPUS INTRICATUS Hass. 

 Plate XLIII. Fig. 1. 



Char. Filaments smaller than those of M. scalaris. Cells Jive 

 or six times as long as broad. Sporangia oval, rather 

 larger than those of M. scalaris, their long diameters being 

 placed in the direction of the width of the cells. 



Sphcerocarpus intricatus, Annals of Nat. Hist. vol. xii. 



p. 186. plate 7. fig. 9. 

 Hab. Broadwater Forest : Mr. Jenner. 



The only differences to be detected between this and M. 

 scalaris are, the smaller diameter of the filaments, and 



M 4 



