Browne — Fauna and Flora of Valencia Harbour, Ireland. 701 



The top of tlie umbrella is ornamented witli a cone-sliaped 

 process, wHcli is very long and pointed in the Valencia speci- 

 mens, and about the same length as the umbrella. 



This species has only been twice recorded outside the English 

 Channel ; by Gosse from Ilfi'acombe, and by Porbes from the 

 Shetlands. 



It may be easily recognised by its two fine crimson or pur- 

 plish tentacles. 



Cladonema radiatum, Dujardin. 



Cladonema radiatum, Hincks, 1868, p. 68, pi. xi. ; Allman, 1872, 

 p. 357, pi. xvii. 



In October, 1898, Miss M. Delap found the Hydroid in an 

 aquarium which had been used for keeping alive various animals 

 taken from the harbour. The Hydi'oid, owing to its minute- 

 ness, was not discovered until it had produced a considerable 

 network of stolons. It was probably introduced into the aqua- 

 rium at the plauTola stage in the process of adding a fi'esh 

 supply of sea- water. 



Early in April lledusa-buds were first noticed upon the 

 hydranths, and at the end of the month a young Medusa was 

 seen swimming in the aquarium. 



The Hydroid, I believe, has not yet been found in its 

 natural habitat, but has always mysteriously appeared in marine 

 aquaria. 



While I was occupying a table at the Plymouth Marine 

 Laboratory in the autumn of 1897, I received from Mi. Eupert 

 Vallentin some adult Medusas of Cladonema radiatum taken in 

 Palmouth Harbour. Two specimens were placed in an aqua- 

 rium, but soon disappeared. On my arrival at Plymouth, in 

 the following April, I found in the aquarium several Hydi'oid 

 colonies of Cladonema, which evidently had developed from the 

 eggs liberated from one of the Medusas. The colonies budded 

 off Medusse during May and June. 



The Medusa is a remarkable creatui'e, for it is able to attach 

 itself by means of special suckers upon its tentacles to any 

 fi.xed object, such as a rock, a piece of sea-weed, or the glass 

 sides of an aquariixm. I often watched the little Medusae in 

 the aquarium at Plymouth, and never saw them use theii' ten- 

 tacles for crawling, but only for attachment. They remain at 

 rest for long periods, with their tentacles expanded on the 



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