350 PODOCRYNE CARNEA. 



Ilahiiat. — On stones in the sea and on old sliclls, chiefly of Gasteropoda. 

 Bathymetrkal didrihution. — Literal to deep-sea zone. 



Localities. — Coast of Norway, Sars ; Bay of Naples, Krohn, Sars, Costa ; Firth of Forth, 

 G. J. A. 



A hydroid which, in all respects, except in colour, resembles that described by Sars as 

 Podocoryne carnea, was found by me in the Firth of Forth growing on stones in rock pools a 

 little above low-water mark, and also on old Buccinum shells in similar situations, and on others 

 brought up from deeper water on the lines of the fishermen. 



My specimens, instead of being pale red, like the Podocoryne carnea of Sars, were nearly 

 colourless ; but I consider this difference of colour as only varietal, and I believe that a white 

 Podocoryne described by Sars as a distinct species imder the name of Podocoryne allnda is, like 

 mine, only a variety of his Podocoryne carnea. 



Sars' account of his Podocoryne carnea is very full, and possesses a special interest in having 

 been given at a time when as yet but few instances were known of the production of free medusas 

 by fixed trophosomes. 



Hincks notices the occurrence in Podocoryne carnea of spiral appendages, like those of 

 Hydractinia echinata, and describes them as occupying the same position near the margin of the 

 colony as the corresponding bodies do in the latter hydroid. He also observed on certain parts 

 of the basal expansion tentacula-like slender filaments, which he compared to similar filaments 

 which have been described in Hydractinia. 



Neither kind, however, was present in any of the specimens that came under my observation. 

 Whatever be the nature of the spiral bodies observed by Hincks, they certainly do not possess 

 the constancy which characterises the spiral appendages of Hydractinia, and it is difficult not to 

 regard both the spiral bodies and the tentacula-like filaments observed by Hincks in Podocoryne 

 as merely abnormal alterations of some of the ordinary hydranths. In well-preserved spirit 

 specimens of a Podocoryne from the Bay of Naples, for which I am indebted to Professor Costa, 

 and which I am unable to distinguish from P. carnea, very delicate capillary filaments existed 

 here and there on the coenosarcal base. These were, however, undoubtedly vegetable growths, 

 though, without careful examination, they might easily have been mistaken for component parts 

 of the colony. 



Krohn, in his account of Podocoryne carnea, published some years after that given by Sars, 

 informs us that the medusa; in his specimens had attained to sexual maturity, and that tiie 

 generative elements, male and female, had been developed in the walls of the manubrium even 

 before the liberation of the medusa from the trophosome ; while a similar observation as to the 

 early sexual maturity of the medusa was made by Chr. Loveu in the specimens described by him. 



Neither in the specimens examined by Sars nor in those which had come under my own 

 observation was there any trace of generative elements. I should feel tempted to regard this 

 difference as indicating a difference of species, but, as no other characters are mentioned by either 

 Krohn or Loven which would justify the separation, I believe it will be better for the present to 

 consider the difference in question as depending on local circumstances, favorable in the one case 

 and not so in the other to an advanced development of the medusa. 



The shells on which Podocoryne carnea is found arc, like those selected by Hydractinia, 

 inhabited in almost every instance liy a hermit crab. 



