i S4 DISCOVERY REPORTS 



Closely related species inhabiting the Subantarctic and the Antarctic also show no clear case of 

 greater size in more southern species. Cnemidocarpa nordenskjoldi and C. drygalskii, for example, 

 attain about the same size. 



Pyura legwnen, P. georgiana and P. bouvetensis inhabit progressively more southern waters but also 

 fail to show any corresponding increase in body size, although there is a striking increase in the length 

 of the stalk. 



It is true, however, that the Subantarctic and Antarctic species of a family are often considerably 

 larger than the temperate and tropical species of the same family. This is particularly noticeable in 

 Distaplta cylindrica and in the molgulids Paramolgida gregaria and Ascopera gigantea. 



REFERENCES 



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Ark. Zool. xviii, no. 35, pp. 1-20, pi. 1. 

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