BOWERBANKIA PUSTULOSA. 523 



Zoarium erect^ phytoid, mucli branched dichotomously, 

 jointed^ branches given ofiF just below a joints blunt 

 at the extremities ; stem flexuous, rather stout^ of a 

 light horn-colour. Zoop.cia ovatCj disposed at intervals 

 in groups along the stem and branches, a group on 

 each internode, subspirally arranged in two series ; the 

 clusters dense, elongated, occupying generally about 

 two thirds of the internode, narrowed below and widen- 

 ing upwards. 



Polypide with 8 tentacles. 



Height 2 or 3 inches. 



From the large size of the clusters of cells, this species 

 has a comparatively stout habit. It grows in tall and 

 dense arborescent tufts, sometimes attaining a height of 

 four inches. The zooecia, during the retraction of the 

 polypides, are contracted above, and, for a short distance 

 below the extremity, transversely striated. Their sub- 

 spiral arrangement is very apparent in the young ter- 

 minal clusters. 



The polypide is furnished with a gizzard, which is small 

 as compared with that of B. imbricata ; indeed there is a 

 delicacy in the entire structure which is wanting in the 

 latter. The oesophagus is very long ; whilst the stomach 

 is short and slender, and pointed below. The setose oper- 

 culum is a remarkably beautiful object, and is composed 

 of about twenty tall and extremely delicate bristles, united 

 by a membranous sheath of extreme tenuity. 



Habitat. On Fuci &c., in shallow water. 



Localities. Isle of Wight (Ellis) : Cork Harbour (J. 

 V. Thompson) : Youghal (Miss Ball) : Dublin Bay 

 (Hassall) : Belfast Bay (W. T.) : Menai Straits ; Llan- 

 dudno ; Ilfracombe, extremely abundant off the Cap- 

 stone; Salcombe Bay, plentiful (T. H.) : Fowey Harbour, 

 and off Goran, Cornwall, very rare (C. W. P.) : Leith 

 shore, rare (D. Laiidsb., jun.) . 



