THE MARINE ALG.E OF NEW ENGLAND. 143 



has never yet been found with cystocarpic fruit, the genus being referred to the pres- 

 ent suborder in consequence of the resemblance of the frond to that of Dumontia. Ac- 

 cording to Bornet, the spores in D.filiformis are borne directly on the cardiogenic cell, 

 whereas in the nearly related genera of Cryptonemiece there are sterile cells between 

 the spores and the carpogenic cell. 



HALOSACCION, Kiitz. 



(From aXg, the sea, and caitKiov, a small sack.) 

 Fronds hollow, tubular or sack-shaped, simple or proliferously branched, 

 consisting of an internal layer of large, roundish, angular, colorless cells, 

 usually arranged in linear series and packed closely together by a gela- 

 tinous substance ; tetraspores cruciate, immersed in the cortical layer ; 

 cystocarpsH 



A small genus, including about ten species, of which H. ramentaceum is common in 

 the North Atlantic, the other species being confined to the North Pacific and ex- 

 tending as far south as California on the east coast and Japan on the west coast. 

 The species are all coarse and somewhat cartilaginous, and are either in the form of 

 elongated obovate sacks or tubular and proliferous. The cystocarpic fruit is unknown, 

 and the genus is placed conjecturally near Dumontia in consequence of the structure 

 of the frond. 



H. ramentaceum, (L.) Ag. (R. ramentaceum, Ker. Am. Bor., Part 

 II, PI. 29 a.— Ulva sobolifera, Fl. Dan., PI. 356.) 



Fronds brownish purple, six to fourteen inches high, cylindrical-com- 

 pressed, attenuated at the base, simple or irregularly branched, more or 

 jess densely beset with scattered or crowded, simple or forked, lateral 

 proliferations ; tetraspores large, spherical, cruciate ; cystocarps 1 



Var. gladiatum, Eaton, Trans. Conn. AcacL, Vol. II, p. 347. 



Proliferations long, simple, somewhat incurved, inflated. 



On algse in deep pools and on mud-covered rocks at low-water mark. 



From Gloucester, Mass., northward ; Xorth Atlantic and Pacific. The 



variety at Eastport. 



A characteristic species of our northern coast, occasionally found at Gloucester and 

 becoming very common at Eastport. The fronds are very variable in shape, yet, on 

 the whole, easily recognized. The most marked form is the var. gladiatum. The 

 robustness depends a good deal on the place of growth. In exposed pools the fronds 

 are short and very densely proliferous; in sheltered harbors, like that of Eastport, the 

 proliferations grow long, and are of rather delicate texture, approaching H. microspo- 

 rum, which hardly seems a distinct species. Kjellman, in Spetzbergens Marina kloro- 

 fyllfiirande Thallophyter, mentions certain hemispherical protuberances on the fronds 

 of this species, and the same are found on our coast. As before stated, the specimen 

 of Aspwococcus compressus credited to Gloucester, Mass., was an error, the specimen 

 being in reality a sterile and partly bleached Halosaccion. 



Suborder GIGARTINE^E. 



Fronds terete, compressed or membranaceous, fleshy or cartilaginous ; 

 antheridia in superficial spots or sunk in small crypts ; tetraspores 



