248 NATURAL HISTORY OP 



of Micropora^ but having an inner chamber occupying 

 the whole of the cavity below, and above narrowed into 

 a tubular passage which either communicates directly 

 with the orifice or opens into a second chamber imme- 

 diately beneath it. — T. H. 



S. Smittii. 



Membranipora andigavensis {Bush). 



This species was discovered by Mr. Peach on the 

 tube of a Serpula off the Cornish coast. 



The zooecia resemble those of Micropora, but have 

 an inner chamber occupying most of the cavity^ and 

 communicating with the orifice by a tubular passage. 



The avicularia are nearly as large in area as the 

 zocecia, and have a prominent dark horn-coloured 

 mandible. 



Genus III. Setosella, Hincks. {Setosa, bristly.) 



Zoarnim incrusting. Zocecia with raised margins ; 

 front depressed and wholly calcareous. Aperture semi- 

 circular. Vihracular cells alternating with the zooecia 

 throughout the colony. Vihraculuni slender and seti- 

 form.— T. H. 



S. VULNERATA, Busk. 



Membranipora vulnerata {Bush). 



Hab. : Shetland, on the very smallest stones at a 

 depth of 80—110 fathoms {A. M.N.). 



The cells are oval, with a raised smooth margin. A 

 little above each cell is a long bristle or vibraculum, 

 whence the generic name is derived. 



Described by Mr. Busk in the Q. J. M. S., viii. 124, 

 and by Mr. Hincks in the Ann. and Mag. N. H., Dec, 

 1877, and July, II 



