172 
Notes . 
nearly alike on the two halves, and corresponds to that of E. crassiim 
rather than of humerosum. Another difference, which is not re- 
presented in a front view, is that the lower is decidedly thicker than 
the upper half, but I was not able to obtain any exact measurements. 
That hybridity should occur among the Desmidiaceae is not in itself 
surprising, several well-authenticated instances being on record in the 
allied Zygnemaceae. Professor Vines has pointed out to me that if 
this is a true instance of hybridity, it must be temporary in its 
character; since, if the individual were to reproduce itself in the 
ordinary way by fission, each half-cell would probably reproduce a 
half-cell like unto itself. 
ALFRED W, BENNETT, London. 
VAUCHER! A- GALLS. —The literature of the so-called ‘galls’ 
on various species of Vaucheria is not very extensive. Benko gives 
a list of those who have observed them up to the date of his paper ; 
but as this paper, which appeared in the ‘ Magy. Nov. Lapok/ vol. vi, 
1882, p. 146, is probably not accessible to the readers of the Annals, 
I transcribe the list from the notice in the ‘ Botanisches Centralblatt/ 
vol. xiv, 1883, p. 1 :• — Vaucher 1803, Lyngbye 1819, Unger 1827 
and 1834, Wimmer and Valentin 1833, Fiirstin Friderike 1836, Morren 
1839, Hofmeister and Cohn 1853, Kiitzing 1856, Magnus 1876, Wollny 
1877 and 1878, Cornu and Balbiani 1874 and 1878, Benko 1882. 
From this list are omitted the only two descriptions with which I am 
acquainted by English observers before that time, viz. : — by Sir J. E. 
Smith in ‘English Botany/ 1st ed., vol. xxv, t. 1765, and Hassall, 
‘ Freshwater Algae of Great Britain/ 1845, p. 56. The only description 
I have met with since Benko’s paper is by Lister, in the ‘ Proceedings 
of the Essex Field Club/ vol. iii, 1884. The earliest figures are 
those by Vaucher, ‘ Conferves d’eau douce/ 1803, t. iii, f. 8, and 
Smith, ‘English Botany/ 1st ed., 1805, t. 17 65; and these, though 
rough, are fairly accurate. I know of no figures later than these, 
except the very admirable ones in Balbiani’s exhaustive account of the 
parasite in the ‘Annales des Sciences Naturelles/ Zoologie, vol. vii, 
1878, t. iv 1 ; and the woodcuts in Listers paper referred to above. 
The species infested by the ‘galls’ is stated by Smith to be 
Vaucheria sessilis , by Hassall V. racemosa. Benko gives the 
1 An abridgment, with the illustrations of Balbiani’s paper, appears in the 
Journal of the Royal Microscopical Society for 1879. 
