226 CHAETOPHORACEAE 
Thallus microscopic, growing within the membrane of other 
algae, irregularly branched.  Cell-division is mostly confined to 
the pointed end cells. Chromatophore a sheet covering most of 
the cell-wall, inclosing a pyrenoid. 
Four to eight zoospores may be formed in any cell and escape 
by a round hole through the cell-wall and host plant; they lack 
a red eye-spot, the number of cilia and manner of germination is 
unknown. 
Inhabitants of salt water, for the most part. Type, E. viridis 
(Reinke) Lagerh. [Etym. voor, within, and 0éppa, cuticle. | 
Hansgirg (89), believing that the type species E»doderma viridis 
was identical with Periplegmatium ceramii Kütz., transferred the 
several species of Endoderma to Periplegmatium. Kützing’s type, 
besides having, so far as can be judged from his published figures, 
a different type of branching from that seen in Exdoderma viridis, is 
described as epiphytic on Florideae while Exdoderma is endophytic. 
Hansgirg's attempt does not seem to have been taken very 
seriously, and reliance has been placed in the judgment of Profes- 
sor Wille (’90) that Endoderma is to be retained. 
1. ExpopERMA WirrRockr (Wille) Lagerheim, Öfvers. Vet. 
Akad. Förhand. 1883”: 75. 1883. DeToni, Syll. Alg. r: 209. 
1889. Wille; Engler & Prantl, Nat. Pflanzenfam. 17: 94. کر‎ 57. 
1890. 
Entocladia Wittrockü Wille, Förhand. Vidensk. Selskab. 
Christ. 1880*: 1-4. 2. 1880; Jahrb. wiss. Bot. 18: 435-437. 
pl. 16. f. 12-14. 1887. Hauck; Rabenh. Krypt. Flor. Deutsch. 
2:463. f. 199. 1885. Collins, Bull. Torrey Club, 18: 340. 1891. 
Periplegmatium Wittrockii Hansg. Flora, 72: 59. 1889; Phys. 
und Phyc. Untersuch. 240. 1893. Mobius, Notarisia, 6: 1291. 
1891. 
Plant a simple or irregularly branched filament, tapering at 
the ends, sometimes forming a small single-layered plate by reason 
of the partial coalescence of the branches ; cells 5-10 م‎ in diameter, 
and 7-12 p long (pl 42, f. 1). 
Exsic.: Phyc. Bor. Am. 265, Nahant, Mass. June, 1893 (F. 
S. Collins). Endophytic between the layers of the cell-wall of 
Elachista fucicola. 
ts: Nahant, July (452). 
Connecticut: Madison, July, August (453). 
