750 PROCEEDINGS OP THE ACADEMY OF [DeC. , 



THE DEVELOPMENT OF GONIONEMA MURBACHII. 

 BY HENRY FARNHAM PERKINS. 



Gonionemus A. Agassiz, 1863, Contrib. Xat. Hist. U. S., IV, p. 350. 



From juvto, angled, and I'^i/J-a, thread, "kneed tentacles." 

 Gonynema Haeckel, 1879, System der Medusen. 

 Gonionemus Murbach, 1895,' Journal Morph., XI, 2. 

 Gonionemus Mui-hacldi Mayer, 1901, Brooklyn lust. Sci. Bui., I, 1. 

 Gonionema A. Agassiz, MSS. 

 Gonionema MurhacMi Perkins, Johns Hopkins Uu. Cir., May, 1902. 



Introduction. 



The genus Gonionema was established by Dr. Alexander Agassiz 

 to include a medusa which he discovered in 1862 in the Gulf of 

 Georgia, Washington Territoiy. Its most striking character, ana- 

 tomically, is the peculiar form of the tentacles, which are bent at 

 an angle near the tip, and at the angle bear a sucking organ by 

 means of which the medusa makes itself fast to any favorable 

 object. This peculiarity in the form of tlie tentacles suggested to 

 Agassiz the name which he proposed. The form of the name 

 which is now used is that which Dr. Agassiz offers in correction of 

 the original one, which was in error as to its ending. 



For a long time the Gulf of Georgia was the only locality from 

 which this genus was described. In 1894, however, another 

 habitat was discovered far distant, at Woods Hole, Ma.ssachusetts. 

 Since then members of the genus have been found at the widely 

 separated localities of the Fiji Islands and Alaska. A closely 

 allied genus has been described from the coast of Brazil and from 

 the Bahamas. Mayer says that he found a new species of 

 Gonionema ("aphrodite") in the Bahamas, but as a matter of 

 fact this medusa possesses rather the characters of the Olindiadre, 

 two distinct kinds of tentacles and papilliform gonads. 



The history of the Woods Hole Gonionema is interesting. In 

 spite of the fact that the " eel-pond " at the centre of the village of 

 Woods Hole, a small body of water connected with the outer 

 harbor by a narrow inlet, is easy of access to collectors, and that 

 numerous students of jelly-fishes had investigated the waters around 



