In i their frond-filaments i verticillosa and U. Wilsoni 



form a group whi ited to U. papillosa p 112 lli-- rationale <>f the lateral 



appendages in < trs to b< as follow 



In tlv ol the frond the main filaments are monostromatically arranged, 



and the lateral a| being generated close up to the apices "l the filaments, are 



on the front and back ol the frond. Il the main filaments 1"- not 



between them is left room for the lateral appendages to spread round 



of the filament and to assume the appearance of investing verticils. 



the base <>t" the frond the main filaments are pluriseriate (apparentl) from the 



correspondingly the lateral appendagi - exhibit a different arrangement. These 



id ii>r the must part, being situated on that side of the filament which is nearest t<> 



the surface of the frond. rhey are sessile when arising from a superficial filament; and when 



arising from the deeper filaments have pedicels of sufficiënt length to enable them to reach the 



surface of the frond. 



Sometimes thej are monostichously arranged, recalling the appearance of U. spinulosa\ 



sometimes they are arranged in two rows mar together, likt- the legs of a caterpillar. In U. 



supra-dichotomial constrictions are absent (fig. 23a), hein- either masked by the 



exuberant growth of the lateral appendages, or never allowed time to form owing to the prepotent 



development of the lateral aj es close up to the ver) apices of the growing filaments. 



Reference was made above to the close affinity existing between the group of U. 

 verticillosa and U. Wilsoni (both West Indian species) and the more primitive East Indian) 

 species U. papillosa. In this latter, opposite papillae occur front and back on its monostromatically 

 arranged upper filaments; while on the lower and basal filaments the papillae are arranged in 

 doublé pairs and even in verticils. They are simple, acute or obtuse ; rarely, at the base of a 

 frond. th< \ are forked. 



U. verticillosa is confined to the Danish West Indies. 



1 \. Udotea Wilsoni Gepp and Howe n. sp. 



Hab. ATLANTIC. Bahamas, Anguilla Isles, Salt Key Bank. North End, /'. Wilson. Howe n" 796S! 



Plant about 10 cm. high, more or less calcified, stipitate. Stipes up to 4 cm. (usually 

 1 — 1.5 cm.) long, simple or branched above, branches free or cemented together. 



Frond composed of a laminated mass of numerous flabellate proliferations arising from 

 one another superficially, and for the most part arising from a position mar and parallel to 

 the central axis of the mass ie. an imaginary prolongation of the stipes upwards). Individual 

 fronds generally semi-cordate at base, semi-rotundate above or semi-flabellate, entire or lobed, 

 striate, sometimes zonate, greyish-green with tlavescent margins when young, cinerascent when 

 old. very minutely spongiose or granulose. 



Frond-filaments 40 — 50;/ in diameter, subparallel, mixed with flexuose intricating branches, 



plun iringly dichotomous, without evident supra-dichotomial constrictions. thickly beset 



or forked, very obtuse lateral appendages. Lateral appendages for the most 



