36 R- T. Günther 



ncarl.v ae(iu:iintcd witli thc marine fauna of the Meditcrranean. 

 In the aiituum of 1852 and in February and March 1853 a uumber 

 üf specimens oi Phyllirhoe bucephala were captured, which were en- 

 cumbcred with a remarkablc appendale hanging from the anterior 

 third of the ventral niargin of the body. 



This "gloekeu-formige Anhang" was tirst chronieled in 1853 by 

 Heinrich Müller who suggested that it might possibly be an ad- 

 hering medusa. In the following year it was again described in 

 somewhat greater detail by H. Müller and Gegenbaur who published 

 the drawing reprodueed in figure 37, but although Ihese distinguished 

 observers alluded to the presence in the "Anhang" of refractile 

 bodies resembling ncmatocysts, they did not venture to give it either 

 a name or a position in the animai kingdom. 



In the raeantime however Krohn fully recognising an affinity 

 with the Gymuophthalmous medusae of Forbes, had endorsed its 

 Claim to be cousidered as the type of a new g-enus which he named 

 after the Danaid 'Shrpx^a. It should however be remavked that Krohn 

 did not quite do justice to H. Müller in writing: "Müller erklärt 

 ihn sonach für ein Organ, dessen Function noch nicht ermittelt sei". 

 This was not thc case. In his tirst announcement of bis discovery 

 Müller suggested that the "Anhang" was a "Qualle", but he also 

 stated the case in favour of the organ theory and left the arbitration 

 for a later observer. 



In 1875 Claus drew attention to the presence of a deep notch 

 in the margin of the umbrella (pl. 3 Fig. 36) and made a compara- 

 tive study of the histology of the muscular tissue of the subunibrella. 



Haeckel in 1880 described Mnestra as a "tetracanale parasi- 

 tische Craspedote" but feit himself unable to include it in his System. 

 "Da bisher weder Gonade noch Otocyste beobachtet wurden, lässt 

 sich ihre systematische Stellung nicht bestimmen." An opinion which 

 was also held by Carus in his Prodromus. 



The present research was bricfly described to the British 

 Association in 1900 and it was tlien stated that in spite of the lack 

 of observations upon the Situation of the gonads, otlier anatomical 

 features had been observed which indicate a dose affinity between 

 Mnest?-a parasites Krohn and ceitain genera of the Cladonemidae 

 and which therefore enable us with some certainty to fix the position 

 of Mucsfm in the .System. It is the object of this paper to give a 

 fuller account of the anatomy and histology of this interesting medusa 

 than has yet appeared. 



