ASSOCIATIONS 117 



from the coast of Ceylon, now preserved in the 

 Colombo Museum, whose tail was beset with a 

 group of barnacles composed of two species, 

 Lepas anserifera and Cone ho derm a hunteri. The 

 barnacles are not ectoparasitic, since they do not 

 feed upon the skin of the snake nor do they 

 assist the snake in any way ; on the contrary, 

 their presence must have seriously impeded its 

 movements. This snake is sufficiently protected 

 from larger enemies by its warning coloration 

 (black and yellow) and by its possession of poison 

 fangs. Moreover, the barnacles thrive equally 

 well when attached to floating bottles and drift- 

 ing spars, and the sea-snake in question was 

 merely their facultative vehicle. 



The relation of barnacles to the skin of sea- 

 snakes is somewhat analogous to a remarkable 

 case of association between certain Hydroid 

 polyps (Stylactis minoi) and a small rock perch, 

 Minous inermis, which has been found in several 

 places off the west coast of India at depths of 

 45-150 fathoms. The skin of the fish is beset 

 with the commensal polyps which have never 

 been found elsewhere, and Colonel Alcock (op. 

 cit., 1902) thinks that they help to conceal the 

 fish from its enemies, in that they play the 

 same part which is, in other cases, performed by 

 frond -like, cutaneous filaments. In both cases 

 feeding is carried on independently of the verte- 

 brate host. The barnacles, named above, are 



H 2 



