THE MARINE ALG^ OF NEW ENGLAND. 57 



BULBOCOLEON, Pringsh. 



(From j3o?.j3og, a bulb, and noleov, a sheath.) 



Filaments branching, creeping, composed of two kinds of cells, one 

 producing numerous zoospores, the other bulbous at the base but drawn 

 out into a tube, from the open extremity of which projects a long flexible 

 hair. 



This genus, consisting of a single species, was first described by Pringsheini in the 

 Abhandlungen der ktinigl. Akademie der Wisseuschaften, Berlin, 1862, who founded 

 it upon a small alga parasitic in the fronds of Leathesia and other Phceosporew, at 

 Helgoland. 



The genus resembles Coleochceie, a fresh- water genus, in the structure of the hairs, 

 but in Bulbocoleon no reproductive bodies, except zoospores produced in the ordinary 

 cells, have as yet been discovered. It is not impossible that oospores may at some 

 time be found, and it will then be necessary to remove the genus from the present 

 order. 



B. prLiFERTJM, Pringsheim, 1. c, p. 8, PL I. 

 Characters* same as those of the genus. 



Parasitic in the fronds of Leathesia tuberiformis and Cliordaria divan- 

 cata. Summer. 

 Newport, R. I. ; Wood's Holl, Gloucester, Mass. ; Europe. 



This minute species is found creeping among the cortical cells of Leathesia and 

 Cliordaria, generally in company with a Streblonema. It forms dark spots on the 

 fronds, and, on microscopic examination, the hyaline hairs are seen projecting above 

 the surface. The species is studied with difficulty when parasitic on Leathesia, owing 

 to the density of the cortical part of the frond, but is more easily examined when it 

 grows on Cliordaria. It was found by Pringsheim on Chorda filum, Chordaria flagelli- 

 formis, and Mesogloia vermicularis, as well as on Leathesia. It probably will be found 

 on several other Phceosporece of our coast, where it appears to be common. 



The following genus described by Reinsch, including a species of which we have 

 not been able to examine specimens, should be included in the account of the Cldoro~ 

 sporew of our coast : 



Acroblaste, new genus of Chroolepideo3. 



Plants microscopic, marine, forming densely aggregated tufts attached to stones and 

 shells ; threads erect, subsimple, branching from the base, arising from procumbent, 

 densely interlaced threads; conceptaoles in the upper part of the branches nearly 

 spherical, at first unicellular, afterwards producing 20-35 spherical zoospores ; after 

 the discharge of zoospores elliptical, with a wide mouth; development of the branches 

 and growth of the threads as in Chroolepus and Cladophora. 



Acroblaste, spec. Contents of cells finely granular, distinctly circumscribed; color 

 slightly glaucous green ; cell-wall thick, sublamellated, twice as* long as broad. 



Height of plant, .336-.6 mm . 



Diameter of filaments, .0050-80 mm . 



Diameter of conceptacles, .0168-196 mnl . 



Diameter of zoospores, .0022 mm . 



Hob. — Attached to shells and stones, Buzzard's Bay, Mass. 



Reinsch., in Botanische Zeitnng, 1879, No. 23, PL 3 o. 



