304 STYLACTIS FUCICOLA. 



medusa at one time and sporosacs at another, a phenomenon of which no sufficient evidence is 

 afforded by any hydroid, and the present form must accordingly be separated, not only specifi- 

 cally, but genericaily, from Podocoryne carnea) 



*i^ 2. Sttlactis rucicoLA, Sars. 



Podocoryne fucicola, — Sars, jNIiddelhavets Litteral-Fauna, p. 40, tab. ii, figs. 6 — 1.3. 

 Stylactis fucicola, — Allnan, in Ann. Nat. Hist, for May, 1864. 



TROPHOSOME. — Hydkorhiza emitting at intervals from its free surface conical 

 cliitinous spines, about half a line in height. Hxdranths about one line and a half 

 in height; those destitute of gonophores having eight to twelve tentacles, those 

 carrying gonophores (proliferous hydranths) much more slender than the former, and 

 with only from four to eight tentacles. 



GONOSOME. — Spokosacs globular, shortly pedunculated, three to seven on 

 each hydranth, scattered or forming an imperfect verticillate group near the middle of 

 the hydranth. 



Colour. — Hydranths pale red, spadix of gonophore pale red. 

 HahUaf. — Attached to sea-weeds a little below the surface of the sea. 



Baih 11 metrical disfribiifioii. — Extending downwards to about a foot from the surface of the 

 sea in the region of Ct/stoseira." 

 Locality. — Messina, Sars. 



' In that most pleasant and instructive book, the ' Sea-side Studies' of Mr. G. H. Lewes, it 

 is stated that in Aglaophenia myriophyllum, a calyptoblastic hydroid, some of the corbulse were found 

 "filled with eggs, and some with medusfe" (' Sea-side Studies,' p. )IQ&). So far as I can gather from 

 the context, it would seem that it is the true phanerocodonic medusa which is here meant, and that 

 the eggs did not proceed from these, but had their origin in sporosacs. There is notliing impossible 

 in this, and coming, as the statement does, from so accurate and conscientious an observer, and so acute 

 a reasoner as Mr. Lewes, who, moreover, has had the rare opportunity of examining living specimens 

 of Aglaophenia myriophyllum, I should not feel justified in at once rejecting it. But for all this, I 

 believe that there is here some error of interpretation. The structure of the Hydroida, and the 

 nature and significance of their zooids, has since Mr. Lewes wrote become much better known ; and if 

 it were really as he supposes, we should have in this case the solitary instance which would invalidate 

 some of the best established generalizations in the whole life history of the Hydroida. 



" The genus Cystoseira replaces round a great part of the Mediterranean shores the Laminaria 

 of our more northern latitudes, and I have named the Bathymetrical region, which is characterised by 

 its growth, the " Region of Cystoseira." Unlike the Laminarian zone of our own seas, it is not 

 necessarily exposed during any period of the limited tide-range of the Mediterranean. 



