ASTERIAS. 97 



§ 3. AsTERiAS Rubens — Reddish-yellow Sea-star. — Plates XVII., 

 XVIII., XIX. 



There is no race of animals wherein the difference and variety of 

 colour is more noted than the Star- fish, and in none greater than in this 

 and the preceding species. Hence the almost insuperable difficulty of 

 discrimination ; nor could I ever decide positively to which of the two 

 Plate XVII. fig. 1 belongs. Presuming them different, I inclined to 

 identify it with the Rubens. I am convinced, however, that two or 

 more have been concentrated as only one ; while a single species in dif- 

 ferent hands is multiplied into more than one. Perhaps the colour is so 

 variable, that observers unable to satisfy themselves of identity, have too 

 readily presumed on difference : all, as akeady explained of other ani- 

 mals. — Nature seems sportive in the detail of some of her works, while 

 prominent leading principles, often unobserved by mankind, are left to 

 determine her purpose. 



The difference of aspect is most conspicuously shown by the subject 

 under discussion. 



In as far as I have been able to observe, the Asterias rnbens ideuti- 

 call}^ resembles the Asterias glacialis in general formation, as well as in 

 the number and proportion of the ox'gans, and in habits. It attains the 

 largest size that I have seen of the Scotish Star-fish, some having been 

 found in the month of June expanding thirteen inches between the op- 

 posite extremities of the rays ; and one obtained in April, expanded no 

 less than fifteen inches. 



The natural or converted colour, if it be not original, seems some 

 shade of j'ellow of various intensity above, and either pale yellow or 

 white below. 



But specimens, of which I could scarcely doubt the identity, have 

 been very different — so different indeed, that representations after colour 

 are scarcely authority. Thus the specimen, Plate XA^II. fig. 1, was of a 

 dull indefinite brownish-grey, while that of Plate XVIII. fig. 1, was a 

 fine vivid yellow. Plate XIX. fig. 1, seen on a reduced scale, was yellow, 

 but not equally fine as the preceding. I have never observed any large 



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