MEDUSAE. 



49 



size has eight groups of tentacles, each group with one long tentacle and four to six 

 minute tentacles or tentacular buds. (Browne, ' Scotia ' Report, p. 244.) I regret 

 that I cannot follow Maas in using the name Couthouyia instead of Desmonema, The 

 latter seems to me to be the correct name to use, and Vauhoffen is also of 

 this opinion. 



I believe that Desmonema chierchianum (Vanhoffen) and Desmonema gaudichaudi 

 (Maas) are two distinct species belonging to the same genus, and I shall also endeavour 

 to show that the Desmonema taken at the ' Gauss ' Winter Station is not Desmonema 

 chierchianum, but Desmonema gaudichaudi (Maas). Before the name Desmonema 

 gaudichaudi can be definitely established for the Antarctic species, the Medusa must 

 be found in the Magellanic area, but I have decided to use the name in this report in 

 preference to introducing a new specific name. Up to the present the records show 

 that Desmonema gaudichaudi (Maas) is an Antarctic species occurring south of 

 latitude 60 ; whereas Desmonema chierchianum is a sub-Antarctic species occurring 

 north of latitude 60. 



Desmonema gaudichaudi can easily be distinguished from Desmonema chierchianum 

 by the thickness and number of the tentacles. The former has up to about seven 

 tentacles in each group, and these tentacles become very thick, 5 mm. or more in 

 diameter. The latter species, Desmonema chierchianum, has a very large number of 

 tentacles, up to sixty in each group, and they are thin and slender, about 2 mm. in 

 diameter. The difference in the number and size of the tentacles is not due to age 

 (Plate V., figs. 1 and 2). 



DESMONEMA GAUDICHAUDI. 

 (Plate V., fig. l.) 



Couthouyia rjaudichatiiU, Maas, 190S, p. 3, PI. I. ('Frangais' Exped.). 



Desmonema chierch-iana, Vanhoffen, 1908 (partim), p. 44, fig. 9, Taf. X., fig. 3, and text relating to 

 specimens taken off the Antarctic continent, ' Gauss ' Winter Station. 



The ' Southern Cross' collection contains three specimens which were taken near 

 the surface of the sea at Cape Adare on 27th December, 1899, and 15th and 17th 

 January, 1900. It is not possible to give a complete description, as the specimens 

 arrived in bad condition. 



Specimen A. The diameter of the umbrella, measured to the periphery of the 

 circular muscles, is about 150 mm. There are eight groups of tentacles, each containing 

 two large tentacles, and four of the groups have au additional small tentacle. The 

 gonads are very much flattened out, and in this condition measured 25 mm. in length 

 and 50 mm. in width. The genital openings are about 35 mm. in length and the 

 spaces between, forming the pillars of the oral arms, are 6 to 10 rum. in width. 



Specimen B. The diameter of the umbrella measured to the periphery of the 

 circular muscles is about 160 mm. The number of tentacles in each of the eight 





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