160 BRITISH SEA-WEEDS. 



very firmly to paper. The cord-like axis is very distinct 

 in some specimens, and has the appearance of a midrib. 

 The spores are described by Professor Agardh as naked ; 

 but Dr. Harvey has since raised a doubt on this point 

 by discovering, with the aid of a high magnifying power, 

 what he believed to be the remains of a very delicate, 

 membranous pericarp. 



Order XVI. WRANGELIACEJS. 



Rose-red, thread-like Sea-weeds, with or without joints, tra- 

 versed by a single-tubed jointed axis. Fructification : — 

 1. Spores formed in the terminal cell of branching threads, 

 which radiate in naked clusters, either from a fixed point or 

 round minute side-branchlets. 2. Tetraspores formed of 

 branchlets shortened to a single cell, naked, not present in 

 all the genera. 



Genus LXVII. WHANG-ELI A. 



Frond thread-like, much branched, jointed, one-tubed ; 

 internodes of the axis naked, or covered with minute cel- 

 lules; nodes clothed with opposite or whorled, jointed 

 branchlets. Spore-clusters terminal in a nest of fibrous 

 branchlets ; tetraspores naked, spherical, triangularly di- 

 vided, seated on the sides of the branchlets. — Wraistgelia, 

 named in honour of Baron Yon Wrangel, a Swedish na- 

 turalist. 



The species of this genus are not numerous, and are 

 mostly natives of warm or temperate latitudes. They 

 were formerly placed in the Order Ceramiacece, between 

 the Griffithsice and Callithamnia, which they externally 

 resemble. They are removed to their present position 

 on account of important differences in their mode of 

 fructification. 



