428 TUBULIPOllID^. 



in mere habit prevails. The branches are decidedly stout 

 and somewhat depressed or flattened, widening gradually, 

 and usually without any abruptness, towards the top. lu 

 a beautiful specimen, however, from Guernsey, Avhich 

 seems to be referable to this species, they terminate 

 above in a triple or double division, and the extremities 

 are rather more expanded than is usual (Plate LVIII. 

 fig. 2). The zooecia are in series ranging from two to 

 three or even four ; in some cases they are disposed with 

 extreme regularity, and the orifices are placed side by 

 side and form a line across the cell (Plate LXI. fig. 1). 

 More commonly there is a certain amount of irregularity; 

 frequently the cells are arranged semialternately, though 

 still preserving their separate grouping. The arrange- 

 ment of the zooecia in more or less distinct series of 2-4 

 is one of the points that distinguish the present form 

 from S. dilatans. 



In the Guernsey specimen, before referred to, ooecia 

 are developed immediately under the terminal tri- or 

 bifurcations ; in other cases they are placed close to the 

 extremity of the branch. They consist of the usual infla- 

 tion of the surface o£ the zoarium, in which a number of 

 the tubes are involved. 



In fresh specimens the surface is usually speckled ; but 

 states are of frequent occurrence in Avhich the zoarium is 

 dense and smooth. 



Habitat. On old shells and stones, chiefly from deep 

 water. 



Localities. Guernsey (A. M. N.) : Cornwall (Couch) : 

 Isle of Man (T. H.) : Northumberland, not common 

 (Alder) : island of Coll (Landsb.) : Sana Island (W. T.) : 

 coast of Antrim, common ; off" the entrance to Belfast 

 Bay, 25-35 fathoms (Hyndman) : Shetland, common to 

 170 fathoms; Hebrides (A. M. N.) : &c. 



