458 DB. G. DICKIE OK SOME ALGiE rOUNB IN 



Loc. Floating in masses, Atlantic Ocean, lat. 12° N., long, 21° 40' W., 

 Captain Thomas Mitchell. 



The general colour is pale green ; under the microscope the 

 filaments are remarkably hyaline, the endochrome consisting of a 

 few spherical granules grouped together in the centre of each cell ; 

 diameter of filaments about '001 (a thousandth) of an English inch. 

 The specimens were for the most part so matted and entangled, 

 that in only a few instances could their form and length be seen ; 

 four short truncated rootlets, each of one row of cells, were ob- 

 served at the base, the other extremity dilated and obtuse ; length 

 1 to 3 inches. 



w 



y 



Fig. 1 shows the general form of the entire plant ; fig. 2, general ap- 

 pearance under the microscope ; fig. 3, transverse section, to show 

 the number of cells. 



With respect to the true original habitat, I agree with Capt. 

 Mitchell in the belief that the plant came in masses from some 

 estuary, and the locality where it was found was merely accidental. 



The other two plants associated with it belong, one to the 

 genus Spermosiraj family Nostochinea?, the other to Schizo- 

 siphon, family Eivulanacea?, The former was free and mi:s:ed 

 with the Kallonema ; the latter was found in small quantity ad- 

 hering to fragments of drift wood. 



Spermosira atlantica, n. sp. Spores subquadrate, single; vege- 

 tative cells mostly in pairs, plano-convex ; persistent cells single, 

 elliptical, 



hoc. With Kallonema. 



Usually eight pairs of vegetative cells and a solitary persistent 

 cell intervene between each spore. The sheath is very trans- 

 lucent, but always sufficiently obvious under the microscope. 

 The filaments have a diameter of -0004 of an English inch, and 

 tlierefore less than half that of Kallonema. 



In the most recent authority known to me, viz. Rabenhorst's 

 'Flora EuropaeaAlgarum,' which usually contains notes on extra- 

 Eiu^opean species, there are four, described under two sections : 

 the first includes those which have several spores in a series and 

 usually no sheath, viz. 8, turicensis, 8. Vriesiana^ and 8. litorea\ 

 one form of the latter, however, has a sheath ; under the second 

 section, where the spores are single or rarely binary, there is one 

 species, viz. 8, spumigcra^ the spores of which are globose ; the 

 species now described is an addition to the second section, and 



distinguished by the form of the spores. 



