370 TUFTS COLLEGE STUDIES, VOL. II, No. 3 



somewhat swollen, fertile much swollen ; cell wall rather thin, 

 chromatophore a rather close network. Mass. Europe. 



The soft, lubricous substance is characteristic of this species, 

 also the great variety in diameter of filaments growing in the 

 same tuft. It is found on exposed rocky shores, in the lower 

 litoral region, in very early spring. 



Family 2. GOMONTIACEAE. 



Fronds consisting of creeping, branched filaments ; cells multi- 

 nucleate ; asexual reproduction by biciliate zoospores or by 

 aplanospores, both produced in sporangia formed on the upper 

 surface of the horizontal layer, and ultimately detached from 

 the same. Only one genus. 



GOMONTIA Bornet and Flahault, 1888, p. 163. 

 Characters of the family. 



KEY TO THE SPECIES OF GOMONTIA. 



i. In marine shells ; filaments 4-8 /* diam. i. G. polyrhiza. 



i. In fresh-water shells ; filaments 12-50 /x diam. 2. G. Holdenii. 



i. G. POLYRHIZA (Lagerh.) Bornet and Flahault, 1888, p. 

 164; 1889, p. CI/VIII, PI. VI, VII; P. B.-A., No. 315. Fila- 

 ments 4-8 p. diam. ; sporangia 30-40 /A diam.; zoospores of two 

 sorts, one 10-12X5-6 yu., the other about 5X3.5 p\ development 

 not known ; aplanospores 4 ^ diam. Fig. 135. 



Abundant everywhere in dead shells on the shore ; the fila- 

 ments penetrating the substance of the shell, branching much 

 and irregularly ; sometimes forming a dense network for a con- 

 siderable distance. It seldom occurs quite pure, but is usually 

 in company with Mastigocolcus testarum L,agerh. and Hyella 

 caespitosa B. and Fl. The three species show as stains on the 

 surface of the shell, each having its own special color ; the 

 Gomontia, grass-green ; the Mastigocoleus blaish- or violet-gray ; 

 the Hyella grayish- or yellowish-green. The latter, however, 

 seldom occurs in sufficient quantity or purity to give its own 

 color to the shell. In studying these species the calcareous 

 matter must be dissolved away ; Perenyi's fluid seems to be the 

 best agent. 



G. polyrhiza probably occurs all along both coasts ; besides 

 inhabiting dead shells, it is found on barnacles, and on the 

 Spirorbis shells attached to Fuci, etc. 



