198 CRYPTONEMIACE.E. v. 



long, lanceolate, not very acute ; sometimes longer and then frequently pinnellated 

 near the end. Along the margin of the naked branches or pinnce, minute gland-like 

 prominences occur at intervals, which I take to be the commencement of pinnules 

 that are often arrested in growth. Here and there a branch occurs, constricted in 

 the middle as well as at the extremities. Many of the branches bear wart-like 

 excrescences. Tetraspores are abundantly found in the lesser pinn.'B, lying among 

 the cortical cells. Colour, a dull brown-red, dark when dry. Suhstame rigid, be- 

 tween coriaceous and horny. It does not adhere to paper. 



^, which I have from Capt. Pike, is very much more slender, with very few 

 branches and scarcely any pinnules. 



The specimens found by Mr. Menzies are of smaller size and more regularly pin- 

 nated than many of Douglas's ; but some of Dr. Coulter's are equally well furnished, 

 and thus the two extreme forms are brought together. 



Plate XXVII. A. Fig. 1. Prionitis lanceolata ; the natural size. Fig. 2, trans- 

 verse section of the frond, showing the cellular structure ; fig. 3, small part of the 

 same, showing the peripheric stratum with immersed tetraspores, and the interme- 

 diate stratum ; fig. 4, tetraspores ; all magnified. 



2. Prionitis jubata, J. Ag. ; " frond flat, pinnately decompound, pinnae linear, 

 tapering at each end, sparingly denticulate at the margin, pinnated above, the pin- 

 nae lanceolate-linear." J. Ag. Sp. Alg. 2, p. 190. Gelidium crassifiolium, Post, and 

 Rupv. MSS. {not of Ch'ev.) 



Hab. Floating in the sea, between Asia and Russian America, Liitke. 



Three or four inches long, or more, sub-stipitate, the primary lamina narrower 

 and thickened. From the upper part of this spring four or five primary pinnae 

 nearly in palmate order, an inch and half long, much attenuated at the base, two or 

 three lines broad beyond the middle, tapering upwards to the truncate apex. 

 Secondary pinnae chiefly towards the apices of the primary, much narrower, 

 scarcely a line broad, naked or very sparingly denticulate, pinnate beyond the 

 middle, pinnules here and there aggregated, alternate or secund, sub-acute. Colour 

 brownish. Substance coriaceous. J. Ag. 



XXII. GRATELOUPIA. Ag. 



^ Frond compressed or flat, carnoso-membranaceous, dichotomous or more frequently 

 pinnate, consisting of two strata of cells ; the medullary of articulated filaments 

 densely interwoven and anastomosing, the cortical of short, moniliform, vertical, 

 closely set filaments. Nuclei ( favello}) immersed beneath the cortical layer of either 



