THE BRANCHING-SYSTEMS OF THE ALCYONACEA. 527 



species L. Jukesii; a second seems to be identical with Quoy & Gaimard's Alcyonum 

 terminale ; the two others are unnamed. 



I have been unable to find any reference to Gray's genus subsequent to the paper of 

 Yerrill's quoted above. It does not ajipear in the ' Challenger' report on the Alcyonaria, 

 although one of the species in tlie British Museum comes from the 'Challenger' collection. 

 The five sj^ecimens which I have examined clearly constitute a distinct genus ; and I 

 have thought it best to retain Gray's name Lemnalia, in spite of the inaccuracy of his 

 diagnosis, and to rewrite the descriptions of the genus and species as follows : — 



Lemnalia, Gray, emend. Bourne. 



Colony an upright fixed authodete; the syndete divisible into a stout, barren, smooth 

 stem, from the top of which a few branches, also smooth, are given ofi'; these, alter a 

 short course, divide, and the tertiary branches thus formed subdivide into terminal twigs, 

 on which the anthocodise emerge. The main stem, branches, and l)ranchlets composed of 

 elongate longitudinally-disposed anthosteles, the more superficial of which appear as 

 longitudinal ribs on the surface. The anthoeodise may be shortly pedicellate or subsessile; 

 their arrangement on a branchlet may be either spicate or racemose. Spicules minute, 

 usually of three kinds: — 1. Elongate fusiform, with more or less prominent warty 

 projections; found in all j)arts of the authodete, except at the extremities of the tentacles, 

 and interlaced in an irregular manner to form a feltwork, specially abundant in the 

 partitions between the anthosteles of the stem. 2. Modified double four-rayed stars, 

 confined to the outer wall of the stem, each star sending a prolongation of one ray inward. 

 3. Scale-like or flattened branched spicules exhibiting a fine sculpture on their surfaces, 

 confined to the distal parts of the tentacles and their pinnules. The anthocodiae not 

 retractile, but the tentacles can be tightly folded over the wide oral disc, their bases 

 thickly beset with sj)icula, forming by their apposition a rudimentary anthopoma. The 

 oral disc spacious, cup-like ; the mouth, generally narrow, leads into a stomodseum, wide 

 and nearly circular in section in its upj^er moiety, tapering below to form a narrow, 

 compressed, richly ciliated tube. The zooids so oriented that their sulcar (ventral) 

 aspects are abaxial, their asulcar (dorsal) aspects axial. 



In all the species of Lemnalia the stem and branches look smooth to the naked eye, 

 but the feltwork of interlacing spicules becomes apparent on microscopical examination. 

 The partitions between the anthosteles of the stem and main branches ai'e not thick, but 

 are densely packed with spicules of the elongate fusiform kind, thus defining the position 

 of Lemnalia among the Siphoiiogorgince. The genus appears to form a link between 

 SiiiJionogorgia and Ammothea, apj)roaching the former in habit and in the development 

 of spicules in the partition- walls of the stem, and the latter in the small size and relative 

 unimportance of its spicules. 



The five species which I have examined fall naturally into two groups : (A) those in 

 wdiich the anthoeodise are subsessile and borne in spikes on the branchlets ; (B) those 



