m 



MARINE FAUNA OF ST. ANDREWS. 



others, by the late Dr. John Beid, who obtained his examples 

 at St. Andrews. 



Hydra tuba. 



On the whole we lack at St. Andrews the splendid profusion 

 of the swimming jellies occasionally met with on our western 

 shores, and especially in the Outer Hebrides, to which a 

 favouring wind and tide sweep them from the warmer area of 

 the Gulf-stream beyond, in company with Ianthina and the 

 Ptcropods. Amongst these the strange and beautifully tinted 

 Diphyes is seen darting hither and thither amongst the brilliant 

 blues of its brethren with its trailing fringes of bright orange 

 polypites ; and on the lonely western shores, as at Monach, 

 countless myriads of the little Velella are tossed in autumn on 

 the sand. 



M r. Darwin *, referring to the colours of certain Invertebrate 

 animals, thinks that it is doubtful if such serve as a protection ; 

 but he goes on to observe that tin perfect transparency of the 

 Medusa;, " many floating mollusca, Crustacea, and even small 

 oceanic fishes partake of this same glass-like structure," and 

 that " we can hardly doubt that they thus escape the notice 

 of pelagic birds and other enemies." It seems to me somewhat 

 * Descent of Man. Sec. vol. i. p. 323. 



