MEDUSA. 51 



16 mm. in diameter, has one long slender tentacle and four to six minute tentacles or 

 tentacular buds in each group. A specimen 25 mm. in diameter has in each group 

 three to six tentacles, one of which is very long and slender, and about six tentacular 

 buds (' Scotia ' Report, PI. II., fig. 2). It is clear that the young stages of Desmonema 

 chierchianum have far more tentacles in each group than Vanhb'ffen's Medora stage, 

 though the latter is larger in size. There is also a difference in the shape of the 

 tentacular lobes. 



Detached Tentacles taken in Nets. The 'Scotia' when in lat. 72 31' S., and 

 long. 19 W., on 5th March, 1904, found in a drift net at 1 to 100 fms. some long, 

 thick tentacles. The longest was over four feet in length and the maximum thickness 

 measured was 7 mm. These tentacles have been described and figured by Dr. Rennie 

 (1905) and considered by him to be the tentacles of a Siphonophore. 



The ' Discovery ' obtained isolated tentacles in McMurdo Sound, and these were 

 also examined by Dr. Rennie (1907), who considered them to be the tentacles of 

 another Siphonophore. "These tentacles differ from those of the Scottish Expedition, 

 both in colour and consistency, the latter being brownish and of a markedly gelatinous 

 nature even in their badly preserved parts. They appear to belong to a distinct and 

 otherwise unknown form." 



Dr. Vanhoffen (1908) has proved, beyond all doubt, the tentacles of Rennie's 

 Siphonophore to be the tentacles of a Desmonema. The ' Gauss ' obtained similar 

 large tentacles at her winter quarters off the Antarctic Continent. 



I obtained from the British Museum a piece of one of the tentacles found by 

 Mr. Hodgson in McMurdo Sound and cut some sections of it. The sections clearly 

 show that Dr. Vanhoffen was right when he said that the tentacles belonged to a 

 Desmonema and not to a Siphonophore. The structure of the tentacles of Dr. Rennie's 

 Siphonophore is similar to that of Desmonema gaudichaudi in the ' Southern Cross ' 

 collection. 



The tentacles of Desmonema chierchianum and D. gaudichaudi are similar in 

 structure, but the muscle bands of D. chierchianum are smaller in size and more 

 slender than those of D. gaudichaudi. As the tentacles of D. gaudichaudi are 

 much thicker than those of D. chierchianum, so also are the muscle bands larger 

 and thicker. 



Distribution. Antarctic Ocean. Booth-Wandel Island, lat. 65 S., long. 66 W. 

 (Paris) (Maas, 1908, 'Fra^ais' Expedition); lat. 69 59' S., long. 82 39' W. 

 (Maas, 1906, 'Belgica' Expedition); lat. 66 S., long. 89 E. (Vanhoffen, 1908, 

 'Gauss' Expedition) ; Cape Adare, lat. 70 18' S., long. 170 9' E. ('Southern Cross' 

 Expedition); lat. 72 31' S., long. 19 00' W. (Rennie, 1905, 'Scotia' Expedition); 

 McMurdo Sound. Lat. 78 48' S., long. 166 20' S. (Rennie, 1907, 'Discovery' 

 Expedition). 



VOL. V. 



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