182 CRYPTONEMIACE^. v. 



nelled segments and rounded axils ; the upper divisions not always regularly 

 dichotomous, but sometimes winged with lateral, secondary segments. Margin of 

 the frond a little thickened and inflexed. Nuclei as large as poppy-seed, thickly 

 scattered over the segments, sphei'oidal, most prominent to the channelled surface 

 of the frond, slightly convex to the convex surface. The plexus of filaments com- 

 posing the medullary stratum is very lax ; the filaments of the cortical layer are 

 minute, moniliform, and densely set. Colour a dark, brownish purple. Substance 

 cartilaginous. It scarcely adheres to paper. 



This plant closely resembles C. crispus in external character, but is of a much 

 softer substance and laxer structure, soon decomposing in fresh water. 



XII. ENDOCLADIA. J. Ag. 



Frond terete, cartilaginous, much branched, muricated with minute spines ; the 

 axis consisting of a single, articulated, monosiphonous filament, coated with minute 

 cells, from Avhich issue whorls of horizontal, radiating, dichotomous, fastigiate, 

 moniliform filaments, whose apices, united by a firm gelatine, form the exterior coat 

 or periphery of the frond. Conceptacks hemispherical, sessile on the ramuli, contain- 

 ing, within a closed pericarp, numerous laxly aggregated nucleoli of angular spores. 

 Tetraspores (according to Kiitzing) exserted, seriated, aggregated in amorphous 

 nemathecia bursting from the tumid upper branches. 



A curious and distinct genus, consisting of two species, one of them a native of 

 the Southern Atlantic, the other of the North Pacific Ocean. The frond has exter- 

 nally the habit of a small Gigartina, but a cross section of the stem, as shown in 

 our Plate XXVIL B.jig 4, shows a very different structure. 



1. Endocladia muricata, J. Ag. ; frond densely tufted, irregularly much branched ; 

 branches flexuous, variously divided, set in the upper part with numerous, divari- 

 cated, awl-shaped ramuli ; the whole frond muricated with very minute, conical or 

 bifid spinules. J. Ag. Sj). Alg. 2, p. 237. Gigartina muricata^ Harv. in Bot. Beechey, 

 p. 409. Post, and Rupr. Illust. p. IG. Kiitz. Sp. Alg. 2, p. 751. Acanthocladia 

 muricata and A. hamulosa, Eupr. ! ! (Tab. XXVIL B.) 



Hab. Sitcha, Dr. Merte^is ! California, Beechey ! Coidter ! Wosnessensky ! Capt. 

 Pike ! (v. s. in Herb. T. C. D.) 



Fronds densely tufted, an inch or two in height, as thick or twice as thick as 

 hog's bristle, irregularly branched ; stems either sub-simple, or once or twice forked, 

 flexuous, having several arching, simple or sub-simple lateral branches, beset, espe- 

 cially toward the ends, with short, crowded, similar branchlets. Both primary and 



