328 BOTANICAL GAZETTE [NOVEMBER | 
as to an influence which the parasite exerts upon it, for it is possible 
that the crowding of the chromatophores from each side toward the 
middle may cause the two enlargements near the middle with the 
constriction between them (jig. 3, G). Not only does the influence of 
the parasite excite these changes in the host cell, but it also causes the 
cell to become more or less strongly arched at the point of insertion of 
the sporangium, the sporangium being in the concavity of the arched 
thread. This effect has only been noted in connection with the 
larger forms, except where the smaller ones are several in a group, 
and here the curving of the thread is slight in comparison with that 
which exists in the case of the larger sporangia. Zopr (I. c.) does not 
mention any similar hypertrophy of the host cell caused by this 
species, nor is it shown in his illustrations. He figures the plant on 
Spirogyra. A. FiscHeEr (/.c.) reports it on various filamentous Con- 
jugatae and Oedogoniaceae, but does not mention any hypertrophy 
of the host. 
Germinating zoospores have been observed in this species in which 
the germ tube may become directed away from the host and develop 
a mycelial tube 15-20 » in length. 
RHIZOPHIDIUM MINUTUM 
This species was collected on Spirogyra varians in a pool beyond 
Forest Home, N. Y. (about one mile from Ithaca), April 23, 1895. 
a It frequently accompanies Lagenidium, but 
Re _ also occurs independently of it. The ane 
rangia are sessile, very small, obpyriform oF 
_ Fic. 4.—Rhizophidium flask-shaped.-. Thus the species belongs to the 
sae nha oehaahe longata section of the genus. The zoosporan 
and aotepceeal: ’ gia are 5-6 # in diameter. At the base are a 
few slender rhizoidal threads which extend 4 
short distance in the host cell content. The form of the 2005? 
rangium thus presents a broad and prominent apical papilla, the end 
of which becomes gelatinized at maturity of the zoospores, forming 
a circular exit pore. The zoospores are few in number, two to four 
in the cases observed. They measure 2. 5 » in diameter, and are 
provided with one cilium and a prominent oil drop. 
Rhizophidium minutum, n. sp.—Zoosporangia obpyriform or flask-shaped, 
broadly papillate, 5-6 # in ae sessile with a few slender rhizoidal filaments 
