MEDUS2B. 9 



The Antarctic species of Koellikeria has fewer tentacles, with smaller compound 

 basal bulbs, than are present in the species found in warm water and there are no 

 ocelli. The absence of ocelli is not a characteristic feature of the Antarctic Medus;e, as 

 Eleutln'ria possesses them. 



The species of DI^IIHHH'IIKI found within the Antarctic region has about seven very 

 thick tentacles in each group, but the species found in the Magellanic region has as 

 many as sixty slender tentacles in each group. 



The new genus, Cosmetirella, of the Mitrocomidse is characterised by possessing no 

 ocelli and no cirri. Their absence shows characters more primitive than are found in 

 the other genera of the family. 



Bathymetrical Distribution. The occurrence of Periphylla at the surface on 

 the Antarctic coast shakes my faith in the term " deep-sea " Medusae, as it is commonly 

 understood. The origin of the name is due to Prof. Haeckel, and is based upon 

 certain Medusae collected by the ' Challenger.'* It is necessary to remember that the 

 nets used by the ' Challenger ' were all open nets. The self-closing net is a later 

 invention, and has not been very extensively used even by recent expeditions. The 

 deep-sea Medusae have been regarded as permanent inhabitants of the lowest zones of 

 the oceans, living in very cold water and in darkness, and carefully avoiding sunlight 

 and warm water. 



Mr. Bigelow (1909) discusses very fully the bathymetrical range of Medusae, and 

 his conclusions are partly based upon the results obtained by the ' Albatross ' in her 

 cruise (1904-5) over the Eastern Tropical Pacific. Both Periphylla and Atolla were 

 taken by the ' Albatross ' within 300 fms. of the surface (one specimen of Periphylla 

 was captured within 200 fms. of the surface). Within the area worked over by the 

 'Albatross' the temperature of the sea at the surface was between 65 F. and 85 F. ; 

 at 200 fms. between 48'5 F. and 567 F. ; at 300 fms. between 427 F. and 48'2F. ; 

 and at 400 fms. 41'9 F. and 42'5 F. Bigelow states that "not a single species 

 was taken in hauls below 300 fms. which was not taken in other hauls between 

 300 fms. and the surface ; although the majority of the genera of Medusae as 

 yet known to belong to the intermediate fauna were taken during the expedition, 

 and several of them in considerable abundance." With regard to the term 

 " intermediate " fauna, Bigelow prefers to adopt " intermediate " in preference to 

 "deep-sea" ("Tiefsee"), as he term is ambiguous from its common application to 

 abyssal bottom animals. 



There is good evidence that some of the deep-sea Medusae extend down to about 

 1,000 fms., but we do not yet know the depth which they usually frequent. Many 

 more hauls with self-closing nets will have to be taken before we can find that out. 



* Cf. The Athfnceum for July 16th, 1881, where the writer (who may safely be supposed, from internal 

 evidence, to have been Professor Moseley) said: "In reality there is no proof that any of the corals came 

 from a greater depth than thirty fathoms. The dredge ranged whilst down from thirty fathoms, or one 

 fathom, or ten fathoms to greater depths ; but there is no proof that it did not pick up the corals at the least 

 depth encountered." ED. 



