VESICULARIADjE : BOWERBANKIA. 377 



the stem and branches and each terminal branchlet is composed of a 

 distinct joint, each of which is perforated by a double row of holes 

 from G to 18 with elevated margins, on all of which in perfect speci- 

 mens are placed oval transparent vesicles, furnished with animals hav- 

 ing 8 tentacula : the rows of perforations having a spiral tendency, 

 the clusters of vesicles hence present themselves in every direction." 

 /. V. Thompson. 



27. BOWERBANKIA,* Farre. 



CHARACTER. Polypidom confervoid, matted or irregularly 

 branched ; the cells sessile, unilateral, irregular, the inflected 

 portion with a spinous or filamentous rim. Polypes ascidian } 

 with ten ciliated tentacula, and a strong gizzard. 



1. B. IMBRICATA, cells ovate or ovato- cylindrical, in dense 

 clusters irregularly scattered on the polypidom. Adams. 



PLATE LXXII. FIG. 5, 6. 

 Primary state. The Polypidom creeping and matted. (Fig. 71.) 



Bowerbankia densa, Farre in Phil. Trans, an. 1837, p. 391, pi, 20 and 21. Johns. 

 Brit. Zooph. 255. W. Thompson in Ann. Nat. Hist. v. 252. Van Beneden les 

 Bryozaires, 29, pi. 4, fig. A. 



Adult state. Polypidom arbuscular, erect. 



Sertularia imbricata, Adams in Lin. Trans, v. 11, pi. 2, fig. 5-11. Turt. Gmel. iv. 

 683. Turt. Br. Faun. 216. Stew. Elem. ii. 450. Tliomp. Zool. Illust. 94, pi. 1, 

 fig. 1-4. Valkeria glomerata, Coldstrcam in Edin. New Phil. Journ. ix. 235, pi. 2, 

 fig. 1, 2: and in Edin. Journ. Nat. and Geog. Sc. iii. 53. Serialaria imbricata et 

 S. verticillata, Templeton in Mag. Nat. Hist. ix. 467, fig. 66. Valkeria imbricata, 

 Johns. Brit Zooph. 254. Hassall in Ann. and Mag. Nat. Hist. vii. 363, pi. 8, 

 fig. 2. Couch Corn. Faun. iii. 95, pi. 17, fig. 2. 



Hob. Parasitical on littoral Fuci and corallines, generally dis- 

 tributed on the British coast. It grows in profusion on the chains 

 of the steam-ferries at Southampton and Portsmouth. 



The polypidom grows in bushy confervoid flaccid tufts rising to 

 the height of an inch and a half, much and irregularly branched, the 

 lower branches spreading and often rooted to the body from which the 

 zoophyte grows. The branches are smooth, transparent, and fistular, 



* Believing it to be new I have named it after my friend Mr. Bowerbank, whose 

 zeal displayed on this as on many other occasions, where the study of natural history 

 may be promoted, was mainly instrumental in inducing me to follow up these investi- 

 gations, on account of the many supplies that I received from him, and I gladly there- 

 fore take the opportunity of acknowledging and recording the obligation that I am 

 under to him." Dr. Farre. 



