131 Transactions. 



and Thyasira flexuosa, Atlantic ; Cassidea pyrum, Lima hullata, 

 and a variety of Cassidea labiata, Japan ; Ancilla rubiginosa, 

 Japan, China, Malacca, Madagascar ; Mytilus edtdis and Saxi- 

 cava arctica, cosmopolitan. Mr. Siiter says the above list is 

 probably far from complete. 



Of shore fishes we have six species which are identical with 

 those of the European seas — namely, Trachurus trachurus, Zeus 

 faher, Conger vulgaris, Scymnus lichia, Echinorhinus spinosus, 

 and Acanthias vulgaris. Our species of Cyttus and Polypriott 

 are representatives of the North Atlantic forms ; and the 

 southern mackerel Scomber australasicus is either identical with 

 or very closely allied to Scomber colias. The genus Argentina, 

 which is characteristic of the seas of northern Europe and 

 the Mediterranean, is represented in New Zealand waters by 

 A. decagon. 



These facts show that there is a good deal of evidence in 

 the character of the littoral marine fauna of New Zealand which 

 makes for the support of the bipolar theory. 



Professor D'Arcy Thompson, in his critical review of Sir 

 John Murray's paper, maintains " that an actual community of 

 forms is not proven, save for a very few forms, some peculiar to 

 the extreme depths of the sea, and others that inhabit the sur- 

 face of the ocean in colder latitudes while represented in the 

 deeper and colder waters of tropical seas " (Proc. Roy. Soc. 

 Edin., xxii, p. 312). The forms enumerated by me, with the 

 exception of Echinocardium australe and perhaps one or two 

 molluscs, are, however, essentially littoral species, which do not 

 extend into deep water, and do not appear to be represented 

 in the intervening seas. 



I have gathered together these scraps, which are, no doubt, 

 far from complete, and if they contain any mistakes I hope 

 they will be corrected by others. 



If there is anything of value in the bipolar theory, and in 

 view of the fact that there are immense differences in the varia- 

 tion of species — some forms remaining unchanged or changing 

 very little through vast geological periods, while others are 

 unstable and change very rapidly — we should expect to find a 

 few species in the Antarctic and sub-Antarctic regions identical 

 with those of the corresponding northern regions, a considerable 

 number of representative species and the genera for the most 

 part common to both areas, with a few genera in all the groups 

 peculiar to each area of distribution in both regions ; and this 

 is, I think, what we find in a comparison of the New Zealand 

 littoral marine fauna with that of the North Atlantic. Near 

 alliance of species is probably more favourable to bipolarity 

 than actual identity. 



