On the Lysianassa magellanica etc. 



9 



pair of the truncal feets have a claw. If we unite the two genera, the 

 geographical distrihution will require some little modification, as becoming 

 somewhat less arctic or antarctic. Of the 13 species of the genus Lysia- 

 nassa 2 are from Greenland and Norway, 7 from the Mediterranean, the 

 Atlantic, England and Norway, 1 from Van Diemens Land, 1 from the Cape 

 of Good Hope, and 2 from Rio Janeiro. None of these species is common 

 to both the arctic and antarctic seas. We have not included the Lysia- 

 nassa magellanica in this calculation, because, as we in the following pages 

 shall show, it constitutes the type of a separate genus. In fact the Cirri- 

 peds are the only other order, in which we have examples of species com- 

 mon to both these zones, for the Lepas Hillii and fascicularis , which are 

 spread over the whole earth (Darwin), are also found in both the above 

 mentioned zones. 



The genus Glyptonotus lias been formed by ElGTHS J ) to define a gi- 

 gantic species of the Idotheidae, found in South Shetland, which approaches 

 the Ldothea entomon and is accordingly generically united with it and with the 

 Ldothea Sabini. It has been called Glyptonotus antarctica ElGTHS (according 

 to Dana). This genus, the geographical distribution of which is, as we 

 have before stated, confined to the polar tracts, although the one species, 

 Glyptonotus entomon (Lin.), as a relic of an extinct glacialfauna (S. Loven), 

 is still occasionally found in more southern parts, as for instance in the 

 Baltic, accordingly presents a most striking and remarkable example of the 

 coincidence of disposition that exists between the two marine polar faunae. 

 The consideration of this lessens in some degree our astonishment, at the 

 discovery of so higly developed a species as the Lysianassa magellanica 

 common to both the arctic and antarctic zones. 



Professor Th. Fries has been kind enough to furnish us with some 

 information relative the Flora of the arctic and antarctic Zones, which we 

 here communicate, as being a valuable assistance in judgeing of the relation 

 between the Faunae of these Zones. "Among the vegetable productions of 

 antarctic America there are not a few found that also belong to the Flora 

 of Europe. The greater part of these however consist of such easily ac- 

 climatized species as Senecio vulgaris, Taraxacum officinale, Sonchus olera- 

 ceus, Galium (marine, Brassica campestris, Capsella bursa pastoris, Stellaria 

 media, Urtica urens etc., which are now found, one may say, spread over 

 the whole world. Among the vegetables which cannot be referred to this 



') Transact. Albauy Institute. II. pag. 331. (according to Dana). 



Nova Acta Keg. Soc. Sc. Ups., III e Seric. 2 



