17 



ECHINODEEMATA. 



BY 



F. JEFFKEY BELL. 



The chief points of interest attached to the « Alert ' collection of 

 Echinoderms may be indicated as follows : — 



Though there are no new Echinoidea, there are some very pre- 

 cious series of some species, Maretia planulata being notably well 

 represented. Similarly the series of some of the Asterids has given 

 us evidence of a variability that would be almost incredible but for 

 the careful registration of the localities of the species. Eare and 

 new forms of Ophiurids and Asterids will, on inspection of the suc- 

 ceeding systematic list, be found to be well represented : OpMoikrix 

 has a large number of forms, the exact delimitation and definition of 

 which has been to me a matter of just as much anxiety and doult 

 as it has been to my predecessors ; but a study of the collection has 

 led me to a somewhat important conclusion, in that I have been 

 compelled by the evidence to attach much less weight than some 

 have done to the characters of the coloration *. 



The question of coloration of forms has taken on almost a new 

 aspect since the publication by Mr. Seebohm of his views as to the 

 value of the pattern of colour in the Turdinse (Cat. Birds B.M. v. 

 p. viii) ; while, on the other hand, the recent statements of such ex- 

 perienced entomologists as Butler, who thinks that in time it will 

 be impossible to decide, without rearing from the egg, whether any 

 form is a species, a hybrid, or a variety (Trans. Ent. Soc. 1880, 

 p. 200), and Elwes, in whose opinion (I. c. p. 134) climate, food, and 

 conditions of life will more than account for the change in tint of 

 certain representative species, seem to indicate that in the group of 

 the Lepidoptera, where coloration has been so much attended to, 

 those who are among the most experienced are learning to doubt its 

 value, and to recognize, as the professed students of ichthyology 

 (see Giinther's ' Study of Fishes,' pp. 176-182) would seem to have 

 done, that in coloration there is great variation. It would be a 

 matter for regret if, when the views of others are advancing, the 

 describer and systematist of Echinoderms should make a backward 



* Liitken, "Le systenie general de coloration constitue un caractere impor- 

 tant qu'il ne faut pas negliger dans la distinction des Ophiothrix" (Yid. Selsk 

 Skr. (5) Bd. 8, ii. p. 104) ; and compare the descriptions of all writers on the 

 genus. 



