1896.] BRITISH HYDBOIDS AND MBDUSvB. 461 



results with hydroids and iiiedusaB have been obtained when the 

 specimen has been killed by a fixiiig reagent, and then placed first 

 into a 2| p. c. solution and finally into a 5 p. c. solution of form- 

 aldehyde. 



I owe my sincere thanks to Professor Weldon for allowing me 

 the use of a table in his Research Laboratory at University College, 

 and for the aid and kind advice which he has So often generously 

 given. To Mr. B. J. Allen, Director of the Marine Laboratory at 

 Plymouth, I am indebted for his kindness in arranging expeditions 

 for the collection of specimens during my visit to Plymouth. 



PabtL— HTDEOIDS AND THEIR MEDUSiE. 



(HXDBOIDA GtMNOBLASTEA.) 



In the first part of these notes the Medusae come under their 

 hydroid names, and are arranged according to Allman's classifi- 

 cation. The synonyms are divided into two sets : the first set 

 contains the names given to the hydroid form, and includes, also, 

 the references to the medusa whilst attached to the hydroid, or 

 reared from the hydroid in confinement. The second set of 

 synonyms refers only to free-swimming medusa9 talten in the sea, 

 which have been usually described under other names. 



Fani. Synooexnida 



Gbmmama iMPiiBxA (Alder). 



Tubularia implexa, Alder (1857). 



Coryne jpelagica, Alder (1857). 



Corytie briareits, AUman* (1859). 



Oo>-i/ne implexa, Wright (1859) ; Alder* (1861). 



Zanclea implexa, Allman* (1864) ; Hincks* (18G8). 



Gemmaria implexa, Allman* (1872) ; Haeckel* (1879). 



* Eeferencea marked with an asterisk denote that medusa-buds upon the 

 hydroid are also referred to. 



Two specimens of the medusa were taken at Plymouth on 

 Aug. 31st, 1895. Both were about 1 mm. in diameter, and corre- 

 sponded to the figures given by Allman in his monograph. The 

 hydroid form has not yet been recorded for the South of England. 



The medusa of Gemmaria implexa is very much like a medusa 

 described by McCrady as Gemmaria gemmosa, found in Charleston 

 Harbour, U.S.A. 



, DiSTUiBUTioN. Scotland — Forfarshire, Allman (H '). Firth of 

 Forth, Wright (H) ; Allman (H). 



England — 30 miles E. of Holy Island, Alder (H). Cullercoats, 

 Alder (H) ; Seaham Harbour, Hodge (H) ; Plymouth, E. T. B. 

 (M'). 



' H = Hydroid form, with or without medusa-bude. 

 M = Free-swimming raedueoid form only. 



