102 NOTAMIIDJ]:. 



differ from it, however, in size, and to some extent in 

 shape ; and one of them bears on its onter side a small 

 and peculiarly formed avicularium. From this second 

 pair two series of zocEcia are developed according to tlie 

 plan which has been already described. 



Scattered here and there over the zoarium gigantic 

 cells frequently occur, resembling in form the ordinary 

 zooecium, but twice as large. They are rendered opaque 

 by their contents, and are very conspicuous objects. I 

 have not been able to make a minute examination of 

 their internal structure; but it is not improbable that 

 they may have a reproductive function. 



Two avicularia are interposed above each pair of 

 cells, except immediately below a bifurcation, where one 

 of them is suppressed. These appendages are given off 

 laterally from a central tube which traverses the pos- 

 terior surface of the zoarium, and bear a very close re- 

 semblance in form to a tobacco-pipe. Some of them 

 are very much larger than the rest, more than double 

 the size, very tumid, and almost of equal width through- 

 out (Plate IV. fig. 5) . 



" This most beautiful pearl-coloured Coralline," as 

 Ellis calls it, has generally been accounted extremely rare. 

 It is certainly local ; but in the south it is not at all un- 

 common"^, and at certain points it occurs in extraordinary 

 profusion. Mr. Busk has told us how common he found 

 it to be in Swanage Bay. In the same locality I have 

 dredged it in large quantities, almost every haul bringing it 

 up (generally in company with the extraordinary Hydroid 



* Dr. Landsborough remarks that " Ri/tiphlcea pmastroides seems its 

 favourite weed ;" and he adds, " from the number of little hittocks whicli I 

 have detected on various weeds frona the South of England, it is evident tliat 

 it is not rare." — Voi). Hint. Brit. Zonph. p. 21)^. 



