132 LIFE BY THE SEASHORE. 



absence of spines. The whole animal, indeed, shows much 

 variation, and it is so common that it is interesting to study 

 the variation in detail for any locality. 



Almost as abundant as the common brittle-star is the 

 daisy brittle-star, which occurs in similar localities. The 

 differences between the two are not very easily described, 

 though an examination of actual specimens should make 

 them obvious enough. Perhaps the most obvious difference 

 is in the spines, which in the "daisy" are short and stout. 

 The arms themselves are wide and flat, less fragile, and not 

 so long as in Ophiotlirixfragilis. They are usually beautifully 

 banded with alternate bars of red and white. There is no 

 difficulty in learning to distinguish these two common 

 brittle-stars by what may be described as mere "rule of 

 thumb," but those who care to make their knowledge exact 

 may welcome a brief account of the more minute peculiarities 

 of the " daisy." Its scientific name is Opliiopholis aculeata, 

 and among its notable characteristics are the fact that the 

 upper arm plates are surrounded by small additional plates, 

 that the disc is so covered by granules that the radial 

 plates are rendered obscure, and that while teeth-papillse 

 are absgnt, three mouth-papillae are present at each side of 

 the mouth-clefts. The spines borne by the lateral arm 

 plates are seven in number, and, as already stated, are short 

 and stout. 



Both the common and the daisy brittle-stars live fairly 

 well in confinement, especially in the case of small specimens, 

 and they are well worth the careful study which can be 

 most readily bestowed on captive specimens. Like other 

 brittle-stars, they are somewhat difficult to study and to 

 name, both on account of the complexity of their hard 

 parts, and of the great colour variability. As regards the 

 question of naming your specimens, one hint may be given, 

 though it is one the beginner is apt to resent it is, do not 

 forget to look at your specimens before you try to name 

 them. Very many people who are interested in natural 

 objects begin systematic work with British flowering plants, 

 and are then apt to acquire the pernicious habit of naming 

 specimens by what one may describe as a mere trick the 

 shape of the petals, or of the fruit, or some other single 

 point. The educative value of species work, however, 



