CYLINDRCECIUM PUSILLUM. 537 



C. dilatatum grows on the frond of a Flustra or the stem 

 of some other Polyzoon, it is inconspicuous and often 

 difficult to detect. But when it spreads over the surface 

 of a shelly it frequently attains a comparatively large size, 

 and is furnished round the edge with a number of spinous 

 projections, which give it very much the appearance of 

 the cell of Buskia nitens. Under such circumstances the 

 species presents a very altered appearance (Plate LXXIX. 

 figs. 1-3). From each side of the dilatation a branch is 

 generally given off a little below the termination of the 

 erect portion of the zooecium ; and frequently one or two 

 more are present. This branching may remind us of that 

 of Aetea amongst the Cheilostomata. 



Habitat. On various Polyzoa and Hydroida, tests of 

 Ascidians, and shells, from shallow to deep water. 



Localities. Antrim (Hyndman) : South Devon ; Ilfra- 

 combe; Llandudno; Isle of Man ; Oban (T. H.) : Cul- 

 lercoats. Coralline zone (Alder) : Shetland, deep water (A. 

 M. K): Wick (C. W. P.). 



Geographical Distribution. Bahusia (Smitt) : Ros- 

 coff, on Cellaria and Lepralia foliacea, abundant (Joliet) . 



CyLINDRCECIUM PUSILLUM. 

 Plate LXXX. fig. 8* ; and Woodcut, fig. 29. 



Zoopcia minute, scattered, tubular, slightly bent, rendered 

 more than semi-opaque by the presence of minute 

 earthy (? sandy) particles in the walls, the lower por- 

 tion decumbent and continuous with the creeping 

 stem. 



Polypides small, with about 10 short tentacles. 



* This figure is defective in not showing the decumbent portion of the 

 cells (see woodcut, fig. 20). 



