196 
A. E. Lechmere. 
Oosysts are terminal or intercalary, either borne singly or in 
a row one behind the other on the main hyphae. They are 
spherical, pear- or barrel-shaped, and vary very much in size. The 
membrane is smooth, usually of a yellowish colour, either with a 
few small spots or not spotted at all. 
The oocysts contain many oospores, up to twenty, in the same 
oocyst. The oospores are spherical, smooth, concentric, 25-30/->t 
diameter, germination unknown. 
Antherocysts are always present, usually very numerous, and 
are borne terminally or in a row one behind the other on the 
antheridial filaments which arise from a separate main hypha 
(diklinous). 
The 5. dioica , de Bary (1883), just described is a clearly 
defined species and must not be confused with the S. “ dioca ” of 
other authors, of which the following are instances :— 
5. dioica, Pringsheim, 1860, Jahr. wiss. Bot. II, Tag. 
XXII., is shown to be 5. Thureti and occurred 
mixed with Rozella septigena in the same culture. 
All species described as 5. dioica by earlier authors 
have also been found to belong to 5. Thureti, as 
none of them showed the diklinous origin of 
the antherocyst, which is the charateristic of 
this species. 
5. dioica, var racemose, de la Rue, 1869. Bull. soc. imp. 
Nat. Moscow, XL1I. This is shown to be really 
5. 'Thureti, from which it is only distinguished 
by the abnormal branching of the main hypha. 
5. dioica, Schroter, Ber. schles. Ges. vaterl. Cult. This 
has also been shown by later authors to be none 
other than S. Thureti. 
II. 5. Monoica, de Bary (1881). 
id. Pringhelm, 1858, Jahrb. f. wiss. Bot. I. 
id. Reineke, 1869, Arch. Mikr. Anal. V. 
Sinon : Diplanes saprolegnoides. Left. geb. 1870, Jahrb. 
f. wiss. Bot. VII. 
Achlya intermedia. Bail, 1860, Naturf. Ver. Konigsberg. 
Saprolegnia spiralis. Cornu, 1872. Ann. des. Sci. Nat. 
Bot. Ser. V, tome XV. (Not a very complete 
description of this species is given, but it seems 
to be very close to S. monoica, from which it 
