Manchester Memoirs, Vol. xlv. (1901), No. 13. n 



The specimen from the Falkland Islands agrees with 

 those from Norway in size, colour, and general confor- 

 mation of the body, in the form and arrangement of the 

 parapodia, and in the minute anatomy of the bristles. 

 The proboscis, with surface papillae, ring of larger papillae 

 at the tip, and the arrangement of the multi-cusped teeth 

 are similar in both cases. 



The two points of difference — the number of teeth, 

 and arrangement of papills on the proboscis — between 

 the Norwegian and Falkland Islands specimens, are not 

 sufficient to necessitate the separation of the latter into a 

 distinct species, for Darwin {Origin of Species, p. 169), on 

 the authority of Bronn, states that " distinct species never 

 differ from each other in single characters, but in many 

 parts." Therefore we may assume that the two forms 

 belong to one species, and that the variation has been 

 brought about by a difference in the conditions of life, 

 probably in the character of the food material. 



But even if we do not regard the two forms as 

 belonging to one species, the fact still remains that the 

 two extra-tropical forms are more closely related to each 

 other than to any known intervening tropical form. 



SpIONID/E. 



Polydora polybranchia. Haswell ('85), p. 273. Carazzi 

 ('93), p. 1 5. Ehlers ('96), p. 87. 



Found in a hollow root of Macrocystis from 3 fathoms, 

 also removed from the bottom of a lighter beached for 

 cleaning (the vessel had not left the harbour for many 

 years) ; also from a small piece of water-logged timber 

 at low water spring tides. 



Distribution.— Sts. of Magellan, Sydney, Naples. 

 New to Falkland Islands, not taken within the tropics. 



