228 



HARDWICKE'S SCIENCE-GOSSIP. 



zooecium and polypide : on the zooecium (or cell) 

 devolving the functions of sexual and non-sexual 

 reproduction ; and on the polypide that of nutrition." * 

 What are called bifurcations of the branches originate 

 in the same way as ordinary fenestrules, with this 

 difference only: the "budding cell" — if I may be 

 allowed the term — instead of originating a lateral 



The formation of some of the forms of PaLrocoryne 

 scotica (Duncan) is by a lateral expansion of what I 

 will call " infertile " dissepiments. In some cases, as 

 in Figs. 171 to 174, these occur on the outer branches 

 of the Polyzoary without any disarrangement of the 

 cells. The ornamentation of the branch is carried 

 into the prolongation, and in Fig. 174 this seems to be 



Specimens of PaLjEocoryne in situ. 



hi r^ 



Wtf 



M 



Fig. 171. — From Richmond, in Fig. 172.— From Hairmyres, in Scot- 



Yorkshire, land. 



The whole of the figures in this part of my communication are pen-and-ink 

 sketches but all are highly magnified. 



Fig. 173. — Lateral Palaeo- 

 coryne, from Richmond. 



Fig. 174. — Bases of cells exposed through fracture. 



Fig. 175. — Trophosome radiatum 

 (Duncan), Richmond, a, portion 

 of tentacular capitulum ; b, tro- 

 phosome. 



U^^ '-•■_. *J ■- 



? a 



Fig. i^.—Paltroco>yne radiatum (Duncan), very much crushed and broken ; Halkyn, North Wales. (See text for description.) 



dissepiment, buds at a slightly different angle, by 

 this means causing a fork-like fenestrule instead of 

 a rectangular one ; and it is the bifurcations that 

 help to increase the lateral expansion of the polyzoary. 



* In the published address of the Professor in the " Trans- 

 actions of the Linnean Society," I regret that I do not find the 

 above admission ; but I am assured that Dr. Allman gave it as 

 reported in the "Zoologist " for July 1878. 



the product of two cells. These "infertile " dissepi- 

 ments are solid ; there is no porosity in any of them 

 to indicate that they were once hollow. Their exist- 

 ence was, from all appearance, for the purpose of 

 reproduction, and so long as they remained unbroken, 

 and attached to the branch, the zooecium had the power 

 of moulding the form of this branch-like projection into 



