40 FREE AND FIXED ANIMALS 



planozoic Annelid worms, both belonging to 

 the family Amphinomidae, Hipponoe gaudichaudi 

 and Amphinome rostrata. The former is some- 

 times found between the valves of Lepas and 

 is coloured pinkish orange like the egg ribbons 

 of the barnacle. This association of forms has 

 been met with on the Atlantic coast of North 

 America, 1 and I have obtained them from the 

 coast of Ceylon. Other planozoic forms with 

 similar distribution associated with Sargassum 

 or Gulf weed are the prawn Leander natator 

 Bate, and the mollusc, Scyllaa pelagica, both 

 of which simulate the colour and foliations of 

 the brown seaweed upon which they live. 



Lepas is specially interesting, as it combines 

 the statozoic with the planozoic habit. As 

 mentioned above, statozoic adults usually have 

 free-swimming or pelagic, i.e., pleotropic larvae, 

 and the nauplius larva of barnacles, at least in 

 its last phase when it is called the metanauplius, 

 already possesses the primordium of the static 

 mechanism, namely, the cement organs in the 

 antennules. 2 Therefore unless there is some 

 special manifestation which Professor Loeb does 

 not explain, it would seem desirable to describe 

 the nauplius larvae as positively pleotropic, or 



1 J. P. Moore, "Some Pelagic Polychseta new to the Wood's 

 Hole Fauna," P. Ac. Philad.^ vol. Iv. part iii., 1903 (1904), pp. 

 793-8oi. 



2 Cf. " Korschelt und Heider. Lehrb. d. vergl. Entwicklungsge- 

 schichte der wirbellose Thiere," Jena, 1890, p. 405. 



