MESOCARPUS. 167 



var. /?. — Sporangia circular. 



Mougcotia scalaris Ilassall, in Annals and ]\Iag. of Nat. 

 Hist. vol. X. p. 45. pi. 7. fig. 7. Zygncma ordinarium ? 

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

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



Half. England ; common, var. /?, Crowboroiigh 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 JNIr. 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 otlier species of the genus described in 

 this paper it ouglit to be referred. The filaments in 3Icso- 

 carpus scalaris, as well as in the majority of the otlier 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 XLIIL Fig. 1. 



Cliar. Filaments smaller than those of M. scalaris. CeWsJive 



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 ividth of the cells. 



Sphcerocarjms intricatus. Annals of Nat. Hist. vol. xii. 



p. 186. plate 7. fig. 9. 

 Hah. Broadwater Forest : Mr. Jenner. 



The only differences to be detected between this and 31. 

 scalaris are, the smaller diameter of the filaments, and 



