MARINE ALG.E OF NEW ENGLAND. 117 



.\«iii>:ii>)i tlit^procarn consists of a short Itranrh coniposed of a fow r»^l!s, the upp«'r of 

 which cnlarjjos and Invars a hair-Hk«' trirho^jym*. The fruit in Xcmalion has no special 

 covoriiii;, luit in Iltlminthora and Ifilmintlioclddia the lower cells of the procarp pro- 

 duce whorls of filaments w hich form an involucre around the spores, an<l in iSciiuiia 

 they i)roduce a meinhranous sack which oprnsat the apex, so that when ripe the fruit 

 consists «)f a conceptacle openinj^ outwards, at whose base is horno a tuft of spores 

 arranj;red in lilaments. With rej^ard to the tetraspores in the pres«'nt suborder, a dif- 

 ference of opinion exists. Contrary to what is found in other Floridccr, the cyst«)- 

 carpic individuals are common, whereas tetrasporic individuals are unknown excei)t 

 in Xemalion, in which •▼enus, on the authority of Agardh, they are borne in the super- 

 ficial cells and arc tripartite. 



XEM ALIGN, Diiby. 



(From vT]U'i, a thread.) 



Fronds gelatinous, cylindrical, solid, repeatedly dichotomous, cortical 

 lilaments 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 tri^iartite in the superfi- 

 ial" cells. (Agardh.) 



A small fjenus, comprising seven or eight species, only one of which, X. muliijidum, is 

 widely diliused. 



X. ^ruLTiFiDU^r, Ag., riiyc. Brit., PI. 3G. [Mcsogloia multifida^ Ag., 

 Syst.) PI. 12, Fig. 1. 



Fronds brownish purple, lul)ricous, two to eight inches long, cylindri- 

 c al, 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 



cystocar])s, but no tetraspores have been seen on ^Vmerican specimens. In the Nereis 



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



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



lit water. Specimens of the present species are so gelatinous as to dry with dilH- 



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



SCi:NrAIA, Bivona. 



(In honor of Domenko Scina, of Palermo.) 



Fronds subgelatinous, dichotomous, cylindrical or compressed, axis 

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

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

 corymbs be;iring large, colorless, cyUndiical cells, which by their juxta- 

 I>osition form an epidermis over the whole frond ; antheridia in small 

 lifts on the superficial cells ; cystocarps bomo just below the cortical 

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

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



