ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
631 
longitudinally on one side of the cell with a central pyrenoid surrounded 
by an amyliferous envelope. He divides the UlotrichiaceaB into three 
sub-families, viz. (1) Chastophoue^j, filaments branching, branches 
ending in a hyaline hair ( Stigeoclonium , Draparnaldia, Chsetophora , &c.) ; 
(2) Ctenoclad[i]e.e, filaments branching, not piliferous ( Ctenocladus , 
Chlorotylium , Chloroconium , g. n.) ; (3) Ulotrichie^:, filaments not 
branching nor piliferous, rarely acuminate ( Hormiscia , Ulothrix , Uro- 
nema). The new genus Chloroconium is thus characterized, — Ramuli 
alterni, omnes aut saltern fftictiferi repentes, ad apicem fructiferi ; 
zoosporse ciliis binis. It includes Chlorotylium coriaceum Borz., Clado- 
phora compacta A. Br., and three new species. 
Leptosira and Microthamnion.* — On similar grounds to those 
mentioned in the preceding paragraph, Prof. A. Borzi now considers the 
genus Leptosira as belonging to the Chroolepidacese rather than to the 
Ulotrichiacese. The cells are of a very light green colour, with a single 
broad parietal chromatophore, whicli often clothes the cavity on all 
sides. In the possession of a single chromatophore and in other 
characters it agrees closely with Microthamnion , and the author proposes 
to classify the genera of Chroolepidaceae in three subfamilies as follows : — 
(1) Chroolepide^e, branches entirely free, each cell containing several 
chromatopliores ( Trentepohlia , Trichopliilus , Gongrosira, Acrohlaste\ (2) 
PHYCOPELTEiE, branches, or at least the fructiferous ones, frequently 
coalescing laterally, and forming a broad disc-like thallus attached to 
the substratum, each cell with several chromatophores ( Phycopeltis , 
Hansgirgia ) ; (3) Microthamnie^e, branches erect, free, each cell with 
a single chromatophore ( Microthamnion , Leptosira ). 
Cell-sap of Valonia.f — Herr A. Meyer has examined the chemical 
composition of the cell-sap of Valonia utricularis. He finds the residue 
on evaporation to amount to 3 * 244 per cent., or somewhat less than that of 
sea-water. Of this, about 0 * 238 is organic. In the relative proportion 
of the inorganic salts, the most noticeable differences from the composi- 
tion of sea-water are the much larger proportion of potassium chloride, 
the much smaller proportion of sodium chloride, and the entire absence 
of calcium salts and of bromides. 
Structure and Reproduction of Chlamydomonas.i— Prof. Goro- 
schankin has confirmed his observations published many years since (in 
Russian) on the mode of reproduction of Chlamydomonas Braunii Gor. 
( C. pulvisculus Dang, non Ehrb.). 
This species multiplies rapidly, under favourable circumstances, in 
the ordinary non-sexual manner. The non-sexual individuals are 
provided with a perceptible membrane, and always with two flagella of 
about equal length with the body ; the chromatophore has the form of a 
cup, at one end of which lies the massive pyrenoid ; the “ eye-spot ” has 
the form of a long slender rod ; and non-sexual propagation takes place 
in quite the ordinary way ; but the sexual mode of reproduction is of a 
very unusual character, owing to the conjugating individuals being 
furnished with a membrane. The larger female individuals containing 
* La Nuova Notarisia, 1891, pp. 387-91. 
f 13er. Deutsch. Bot, Gesell., ix. (1891) pp. 77-9. 
J Bull. Soc. Imp. Nat. Moscou, 1890 (1891) pp. 498-520 (2 pis.), 
2 y 2 
