ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
91 
attributed to it. Goncitoblaste is founded on a new species, G. rostrata , 
endophytic on a Zygnema. The zoospores germinate within the gelatinous 
envelope of the host, developing a hyaline bristle which is cut off by a 
septum, and sharply bent at the base. Endoderma is divided into two 
subgenera, — (1) Entocladia, in which the cells are destitute of hairs, and 
contain usually only a single pyrenoid ; it is made up of a new species, 
E. perforans, endophytic on dead leaves of Zostera , together with others 
previously described ; (2) Ectochaete, which includes one species hither- 
to known and two new ones, — E. leptochsete , endophytic on a marine 
Chsetomorpha, and E. Jadinianum on a freshwater Gladophora. Pliseophila 
Floridearum occurs on a great variety of marine algae. Chsetosiphon is 
founded on a new species, G. moniliformis , found on Zostera and asso- 
ciated with Endoderma perforans. The following diagnosis is given : — 
Thallus tubulosus, continuus, per cellulas lacunasque foliorum Zosterse 
marinse longe excurrens, irregulariter ramosus, septa cellularum per- 
forans, ibique valde constrictus, extus setas longas hyalinas leniter con- 
tortas emittens. Chlorophora parietalia discoidea polyedria, pyrenoidea 
singula foventia. Sporangia ex partibus thalli septo discretis formata ; 
zoogonidia 2-ciliata, ex divisione contentus sporangii orta, per tubulum 
hyalintim emittuntur. Blastophysa and Chsetosiphon form together a 
group presenting strong resemblances both to the Siphonocladeae and 
to the Valoniaceae, for which the author proposes the name Ch^eto- 
SIPHONACE2E. 
The epiphytic and endophytic groups are distinguished by the 
portion of the thallus which is in contact with the substratum being 
dorsiventral in the former, but not in the latter ; the membrane is less 
mucilaginous in the latter than in the former. The hairs are enclosed 
in a sheath only when the thallus is disc-shaped. The cells of the 
epiphytic species have only one pyrenoid, while there are several in 
the endophytic species, with the exception of Chsetonema , Gonatoblaste , 
and Entocladia. The zoospores in each zoosporange are more numerous 
in the marine than in the freshwater species. A sexual mode of repro- 
duction by isogametes has been observed in some genera. 
Zoospores of Draparnaldia.* — Mr. L. N. Johnson has observed the 
structure and the mode of formation and escape of the zoospores of 
Eraparnaldia plumosa. Their production is confined to the branchlets, 
but to no particular part of them. The zoospores germinate freely, and 
no sign of conjugation between them was detected. Resting spores were 
also observed, which are probably modified zoospores, but differ from 
them in the absence of the pigment-spot and of the two contractile 
vacuoles. 
Chgetomorpha Henningsii.f — Herr P. Richter has observed the 
escape of swarm-spores from this alga ; they are sometimes formed in 
isolated cells, sometimes in several adjoining cells ; they have no red 
eye-spot. The escape takes place through an opening in a previously- 
formed papilla. No conjugation of swarm-spores was observed. Some 
of the vegetative cells develope, at the end of the season, into akinetes. 
In addition to the ordinary mode of vegetative multiplication, a separa- 
* Bot. Gazette, xviii. (1893) pp. 294-8 (1 ph). 
t lledwigia, xxxii. (1893) pp. 310-5. 
