40 r diversity of California Pnhlic-ations in Botany [Vol.8 



the cells all yeniaining witliin a common tegument; then at maturity 

 each small coll of the colony divides into a few gonidia, the whole 

 mass of teguments and cell walls dissolves, thus setting free the gonidia. 

 The other line of development starts likewise witli a single cell. This 

 continues to increase in size without division until maturity is reached 

 when it is many times larger than the vegetative cells in the other 

 method of development, after which the whole protoplast divides into 

 gonidia, either by successive or by simultaneous divisions. , These 

 questions need further observation and study before any decision of 

 value can be made concerning them. 



11. Hyella B. and F. 



Plants forming tangled masses of indefinite expansion, boring into 

 shells of mollusks or into other algae ; primary or basal filaments mainly 

 extending horizontally, one or more rows of cells enclosed within a 

 sheath, often very much crumpled and contorted, with frequent true 

 branching, composed of a series of cells practically independent of 

 one another ; short secondary filaments composed principally of longer 

 and narrower cells enclosed in a separate sheath arising from the basal 

 filaments ; cell divisions in all directions ; reproduction is accomplished 

 by the escape of vegetative cells from the sheaths, and by gonidia 

 formed by the successive divisions of the contents of gonidangia devel- 

 oped on short branches of the basal filaments or by the modification 

 of cells of the basal filaments. 



Bornet and Flahault, Note sur deux nouveaux genres d'algues 

 perforantes, 1888, p. 163 (p. 3, Repr.). 



The type species is Hyella oaespitosa B. and F., but the type speci- 

 men is not definitely designated. The two localities explicitly indi- 

 cated are those of Croisic in Brittany, on the Bay of Biscay and Cette 

 in Languedoc, on the Gulf of Lyons. Since the locality mentioned 

 especially as the source of the material is Croisic (Bornet and Flahault, 

 Sur quelques plantes vivant, 1889, p. 3), we have assumed this as the 

 type locality. 



The genus Hyella is dimorphous and presents an interesting and, 

 to some extent, puzzling morphology. It is distinctly filamentous and 

 in general appearance suggests the Stigonemataceae. At first a layer 

 is formed at the surface of plant or shell, which appears chroococcoid 

 but which seems really to be filamentous of the complex type of Stigo- 

 nema. From the inner face of this layer branches are given off which 



