MARINE ALG2E OF NEW ENGLAND. 117 



NemaUon theprocarp consists of a short branch composed of a few cells, the upper of 

 ■which enlarges and bears a hair-like trichogyne. The fruit in NemaUon has no special 

 covering, but in Helmmthora and Helminthocladia the lower cells of the procarp pro- 

 duce whorls of filaments which form an involucre around the spores, and in Scinaia 

 they produce a membranous sack which opens at the apex, so that when ripe the fruit 

 consists of a conceptacle opening outwards, at whose base is borne a tuft of spores 

 arranged in filaments. With regard to the tetraspores in the present suborder, a dif- 

 ference of opinion exists. Contrary to what is found in other Floridece, the cysto- 

 carpic individuals are common, whereas tetrasporic individuals are unknown except 

 in NemaUon, in which genus, on the authority of Agardh, they are borne in the super- 

 ficial cells and are tripartite. 



NEMALION, Duby. 



(From vrjiia, a thread.) 



Fronds gelatinous, cylindrical, solid, repeatedly dichotomous, cortical 

 filaments corymbose, giving off descending branches, which unite with 

 the axial filaments ; antheridiain tufts on the superficial cells; procarps 

 borne at the base of the corymbose branches, consisting of few cells ; 

 cystocarps immersed, without special covering, sporiferous filaments 

 radiating from the trichophore; "tetraspores tripartite in the superfi- 

 cial" cells. (Agardh.) 



A small genus, comprising seven or eight species, only one of which, N. multifidum, is 

 widely diffused. 



N. multifidum, Ag., Phyc. Brit., PI. 36. (Mesogloia multifida, Ag., 

 Syst.) PL 12, Fig. 1. 



Fronds brownish purple, lubricous, two to eight inches long, cylindri- 

 cal, several times dichotomous, axils obtuse. 



On exposed rocks at low- water mark. Summer. 



From Watch Hill, E. I., northward ; Europe. 



Not uncommon on rocks exposed to the action of the waves. Commonly found with 

 cystocarps, but no tetraspores have been seen on American specimens. In the Nereis 

 the species is said to have been collected at Bangor, Maine, by Mr. Hooper. This 

 must be an error, however, since Bangor is on the Penobscot River, above the limit of 

 salt water. Specimens of the present species are so gelatinous as to dry with diffi- 

 culty. They should be exposed in the air for two or three hours before pressing. 



SCINAIA, Bivona, 



(In honor of Domenico Scina, of Palermo.) 



Fronds subgelatinous, dichotomous, cylindrical or compressed, axis 

 small, composed of slender colorless filaments, horizontal filaments end- 

 ing in short corymbs of small, round, colored cells, the centers of all the 

 corymbs bearing large, colorless, cylindrical cells, which by their juxta- 

 position form an epidermis over the whole frond ; antheridia in small 

 tufts on the superficial cells ; cystocarps borne just below the cortical 

 layer, consisting of membranous sacks opening externally, with a tuft 

 of spore-bearing filaments attached to the base ; tetraspores unknown. 



