82 ZYGOPHYCEE. 
rent. Indeed, having sent specimens to several celebrated algologists, 
they hesitated to admit it into Tyndaridea, until Mr. Hassall, who also 
at first strongly doubted whether it belonged to the Conjugate, fortu- 
nately gathered fertile specimens. Such we ourselves found shortly 
afterwards, and we have since repeatedly met with them; the appear- 
ance of the plant in conjugation, however, is so altered that its identity 
can only be determined by tracing it through all its changes. 
“Tn its usual state the sheath is very conspicuous, and the dense en- 
dochrome go fills the cells that the plant looks like a Conferva, the con- 
tinuity being interrupted merely at the dissepiments. When about to 
conjugate the sheath has nearly or altogether disappeared, and the en- 
dochrome is collected into two stellw, leaving the rest of the cell colour- 
less.” — Ralfs. 
Hassall also found and examined the plant, and figured it with zygo- 
spores .in the cells of the filaments, whereas the Continental species, 
since the figure by Kutzing, is always described as having the zygospore 
in the canal of conjugation. There cannot, therefore, be the slightest 
doubt that the species found by Hassall and Ralfs is quite distinct from 
that known to Kutzing, Rabenhorst, and De Bary. Priority certainly is 
in favour of Hassall’s name, and it is the Continental species which must 
give way, and yield up a name, acquired in error, to its rightful claimant. 
Our figures are based on the sketches and drawings by Ralfs, with 
whom we have been in communication on this question. It is absurd to 
suppose that Ralfs and Hassall were both deceived, as well as Mr. 
Jenner (an admirable observer), to whom the species was undoubtedly 
known, and finally Mr. Salter in preparing the drawings from the 
specimens for the “ English Botany.” Unfortunately we could find no 
fruit in the specimens which we possess, collected by Ralfs forty years 
ago, nor could we obtain specimens in conjugation from Cornwall during 
the past spring. 2 
Plate XXXTI. fig. 1. a, 6, portions of sterile threads X 400; ¢, 
fertile cells with zygospores X 400, after Ralfs; d, conjugating cells X 
400. 
Zygnema leiospermum. De Bary. Rabh. Alge Exs. No. 638. 
Sterile cells equal in length and breadth, or sometimes twice 
as long. 
Zygospore globose or broadly oval, formed in one of two 
conjugating cells; membrane brown, even. 
Sporiferous cells a little swollen. 
Size. Cells -022 mm. diam. Zygospore -023--03 mm. 
De Bary Conj. p. 77, t.1,f. 7-14. Rabh. Alg. iii. 249. Kirsch. 
Alg. Schl. p. 125. 
In ditches filled after rain. 
The two British species with the membrane of the zygospore even, 
in this section, are the present and the following, which will require 
some care in the discrimination. The inflated cells, which enclose the 
zygospores, in the present, is relied upon as one of the features which 
distinguish it from the succeeding species, as well as the larger size of 
the zygospores. 
Plate XXXI. fig. 2. u, portion of fertile thread X 400; 4, ¢, 
fertile cells, with zygospores, after De Bary X 400; d, mature zygospore 
X 400, after DeBary. 
