14 



MR JAMES RITCHIE 



comb — the compressed gonangia — from among which spring many short, uncoiled tubes 

 0"4 to 0"5 mm. in length. 



Locality. — Burdwood Bank. Lat., 54° 25' S. ; long., 57° 32' W. Depth, 56 

 fathoms. 1st December 1903. 



As the species was named by Allman from small fragments, and as subsequent 

 specimens collected by Paessler in 1893 off Australia were also fragmental, T have 

 thought it necessary to give a rather full account of the structure of the colony to 

 supplement the original description. Since Hartlatjb figures only longitudinal and 

 transverse sections of the coppinia (Hartlatjb, 1905, p. 597), representations of the 

 general appearance and magnified surface view have been here included. 



Brucella, nov. gen. 



We have named this genus after Mr Bruce, the leader of the expedition. 



Generic Characters. Trophosome. — Stem and branches fascicled for the most 

 part, becoming monosiphonic distally ; consisting of an axial tube predominantly 

 hydrotheca-bearing, surrounded by peripheral tubes which may occasionally bear 

 hydrothecEe and nematophores. Hydrothecse tubular, fastened by their bases to a 

 process of the hydrocaulus, their cavity being distinctly differentiated from that of the 

 peduncle. Each hydrotheca is accompanied by a basal pair of nematophores. 



Gonosome. — A coppinia, that is, a bunch of clustered gonangia surrounding the 

 hydrocaulus, from which a number of delicate tubes arise. 



The genus shows affinities with Perisiphonia, AUman (Allman, 1888, p. 43) and 

 Zygophylax, Quelch (Quelch, 1885, p. 4). From the former it can be distinguished 

 by its manner of fascicling, its arrangement of nematophores, and, perhaps not so 

 certainly, by the shape of the hydrothecee. The chief points of difference are 

 summarised in the following table : — 



Perisiphonia. 



Axial tube completely enveloped. 



No liydrothecse on peripheral tubes. 



Nematophores frequent and regular on peripheral 



tubes. 

 Nematophores present or absent from axial 



tube. 

 Hydrothecse flask-shaped. 



Brucella. 



Axial tube not completely enveloped. 



Scattered hydrothecae on peripheral tubes. 



Nematophores scattered and irregular on the peri- 

 pheral tubes. 



Two nematophores at base of each hydrotheca on 

 axial tube. 



Hydrothecae tubular. 



From Zygophylax, to which it is] closely allied, it can readily be distinguished by 

 the distinct difterentiation of the hydrotheca cavity from that of the peduncle, and by 

 the scattered nematophores on the peripheral tubes. 



A portion of a specimen when softened in caustic potash and dissected, showed a 

 central, predominantly hydrotheca-bearing tube, surrounded by peripheral tubes, w^hich 

 were sometimes simple, sometimes branched, and sometimes bearing scattered hydro- 

 thecae and nematophores. The structure of the fasciculation seemed to resemble that 



(rot. soc. edin. traxs., vol. xlv., 532.) 



