136 



The avicularia, of which there are two i)roxinialIy to the frontal area, are 

 in the oa'cia-hearing zoa-cia situated on the distal part of the ocrcium. 



The vibracula are not found on all zoa-cia, hut seem to ai)i)ear rather fre- 

 (juently and may be seen sometimes on 2 — 3 successive zooecia. They are narrow, 

 most often angularly bent and situated in such a way that their inner part is 

 turned obliquely inwards and towards the proximal end. A radical libre takes 

 its origin from their outer part, while other radical fibres spring from a pore- 

 chamber in the zooecia, that have no vibraculum. 



The ooecia are provided with fine radiating striae, and the largest part of 

 the ectooa-cium is uncalcified. The calcified jjart terminates in a somewhat 

 projecting, angularly bent or arched, often somewhat sinuated margin. 



The colony is not jointed. Its branches may have up to 7 rows of zooecia. 



By way of exchange I have acquired a small fragment of this species (from 

 Challenger, St. 313) from the Zoological Museum at Dundee. 



Hoplitella n. g. 



Avicularia appear only on marginal zoaxia which all have a large avicularium, 

 the inner half of which is immersed; the distal wall has on each side a long, 

 narrow continuation running along the corresponding lateral wall; the entire 

 frontal surface membranous; no oa'cia; the colony not jointed. 



H. armata (Busk). 



Carbasea armata Busk, 



Catalogue of Marine Polyzoa, Cheilostomata, p. 50, PI. L, figs. 1, 2. 



Flustra armata Waters, 

 Jom-n. R. Micros. Soc, 1899, p. 279— 2Sfi. 

 (I'l. II, figs. l();i — lOo). 

 The zooecia, the entire frontal surface of which is membranous, are rhombic- 

 like oval, each of their lateral margins, when seen from the frontal side, ending 

 in an almost rectangular edge, bounded l)y two curved lines. While this edge in 

 the zooecia in the median part of the branch is generally situated a little distally 

 to the centre on the inner and a little proximally to the centre on the outer 

 lateral margin, it is, on approaching the margin of the colony, situated higher 

 up on the former and further down on the latter, and this contrast is always 

 greatest in the parts of the colony, which have the largest number of rows of 

 zocecia. The marginal zoa^cia are much broader than the others, as they partly 

 enclose the large avicularia, and as they stand in close relation to the avicularia, 

 it will be more natural to treat them together with these. Immediately proximally 



