SPECIES OF CALLOPHYLLIS AND EIIODYMENIA. 70 



dried specimens are from 1 millim. to 1*5 millim. wide. They 

 appear in equal numbers on both sides of the thallus quite simi- 

 larly and slightly darker in colour than the other portions of 

 the frond. They are scattered over the whole of the upper part 

 of the thallus. 



A transverse section through the mature fruit shows that the 

 cystoearp is oval, equally projecting on both sides of the segment, 

 and possessing a fairly thick wall. This wall consists of a varying 

 number of cells, the outermost being the smallest and the two 

 outer layers being arranged at right angles to the surface of the 

 thallus. In this wall, but on one side only, is the opening for 

 the expulsion of the spores, usually a single ostiole, but occa- 

 sionally two. The part of the w r all where the ostiole is formed is 

 thicker, and from the cells at the side of a pore project thread- 

 like cells at risrht angles to the ostiole. The ostiole is widest at 



o"" "-"o 



the point nearest the inner part of the fruit- nucleus, and is 

 contracted at the cortical part of the fruit-wall. The nucleus 

 itself consists of a varying number of spore-clusters arranged 

 quite irregularly, and separated by thin walls of interwoven 



filaments very close in texture. 



This structure of cystoearp confirms the opinion with respect 

 to this specimen, that it does not belong to the genus llhody- 

 menia, and shows that it is a species of Callophyllis. Compared 

 with the different species hitherto described it completely agrees 

 with Callophyllis obtusifolia, J. Agardh (figured in Agardh, ' Mor- 

 phologia Floridearum,' pi. xiv. figs. 1 & 2). 



II. 



I have closely studied only one of the two specimens named as 

 Rhodymeniapalmata, Grev. (from Dickie's herbarium), collected 

 by Dr. Anderson at Santa Cruz (Bay of Monterey), and now in 

 the Natural History Museum; the other I have not been able to 

 examine so thoroughly. This last bear* some resemblance to the 

 first specimen ; but is also, even from its outer form of thallus, 

 not a typical specimen of Bhodymenia palmata, Grev. The ana- 

 tomical structure of the thallus agrees, in general, with Callo- 

 phyllis obtusifolia, J. Agardh, but differs from the first of Dickie's 

 specimens in details of structure. The centre layer consists 

 of large cells three or four deep, and not, as in the previous 

 specimen, two or three; the interstitial cells are somewhat 

 smaller than in the other plant : the points of contact of the large 



