THE MARINE ALG.E OF NEW ENGLAND. 1^1 



Fronds thin, orbicular, bei'oniinjj: conHuent, distinctly zoiiatc; lietcro- 

 cysts i)resent, basal cells elon«iatcd-rcctan«^ular, cortical cells semicircu- 

 lar or triangfular seen tVoni above; tetrasporic concei)tacles small, hemi- 

 si)lierical, orilice not plainly ciliate; tetraspores luurparted ; antheridia 

 and cystocarps ? 



On Fucun vcsiculosus. 



AVood's IIoll, Mass; in all parts ot tiie world. 



Altli(>u;>:l» •»i>ly ono locality is iiu'iititmed, the spccifs prohably occurs tliroii<iliont 

 our Hunts. It is (listiu«^uislu'(l from the last hy the shai>e of the conceptacles and the 

 abseuco of a circle of cilia around the orilice. The fronds are lary:er and more fre- 

 4iucn«ly orbicular, although scarcely thicker than in M. LcjoVm'x. In hoth species the 

 calcareous incrustation is somewhat farinaceous as compared with the following, in 

 which the incrustation is smoother and solid. M. mcmhranacea^ Lam.x. related to M, 

 faritiosa, but destitute of heterocysts and having tetrasporic conceptacles with several 

 orilices, is to be exju^ctcd on alg;e of our coast. 



M. PUSTULATA, Lam.x. (J/, inistulata^ Pbyc. Brit., PI. 347 d ; Eosa- 

 nofi; 1. c, n. 4, Figs. 2-8.) 



Fronds rather thick, circular, becoming reniform or orbicular, indis- 

 tinctly zoned ; heterocysts wanting, basal cells elongated vertically, cor- 

 tical cells squarish; conceptacles large, hemispherical, oritice naked; 

 tetraspores four-parted. 



Probably common on the larger alg.T along the whole coast, but being nndistinguish- 

 able froui the next species when sterile, one cannot be sure of the species unless it is 

 in fruit. The tetraspores of M. pmiulata are zonately four-parted, while those of M. 

 macrocarpa are merely two-parted at maturity. In both species the fronds are rather 

 thick and solid and do not crumble, as in the two preceding species, and the orbicular 

 shape is preserved for a longer time. 



M. MACROCAEPA, Eosanoft". {M. maerocari)a^ 1. c, p. 74, PI. 4, Figs. 

 2-8 and 11-20.) 



Fronds as in M. imstulata ; tetraspores large, two-parted. 



On Chondnui. 



Gloucester, Mass. ; Europe. 



h. Species rather larr/e, groiciiuj on stones and shells^ cortical stratum 

 icell developed. 



M. Lenormandi, Aresch. {Lithophjlhnn Lenormandi^ Rosanof!', 1. c, 

 p. 8o, PL V, Figs. IG, 17 ; PI. A'l, Figs. 1, 2, 3, 5.) 



Fronds saxicolous, closely adherent to the substratum, suborbicular, 

 l>ecomiug squamulose-imbricate, slightly zonate, margin crenate, lobed ; 

 tetraspores four-parted, in compressed, hemispherical conceptacles, with 

 numerous orifices; antheridia and cystocarps! 



On stones. 



Gloucester, Mass. ; Europe. 



Apparently common in many places, but fniiting specimens were only collected at 



