122 CATALOGUE OF THE ECHINODEBMATA OF 



Contrasting this with the results given by Mr. Norman of the 

 dredgings in the Shetland Seas, we are very far behind. He 

 records — 



Crinoidea 2 



Ophiuroidea 14 



Asteroidea 17 



Echinoidea 15 



Holothuroidea 14 



62* 



Or nineteen more than we are able to do. Still, considering the 

 extent of ground, and the varying and great depths they dredged 

 over, with those extraordinary influences which tend to pro- 

 duce a superabundance of animal life in these seas, as compared 

 with our own, we cannot fail to fall far short. It is probable, 

 however, that the list here given may compare favourably with 

 the catalogues from other localities of a similarly restricted cha- 

 racter. 



I am far from being satisfied with the state in which I am 

 obliged to leave the Ur asters (Asterias). Several "forms" have 

 utterly defied my repeated attempts to define where one species 

 may be said "to begin" and another "to end." Hundreds of 

 specimens have been collected and examined during the last few 

 years. Sometimes it was thought they could be "split up" in 

 consequence of marked differences which appeared important, 

 at another time a doubt would occur, upsetting previous con- 

 clusions. I fear, therefore, like other observers, I must leave 

 them much as I find them, and avoid what undoubtedly would 

 be a great evil — the setting up of specific distinctions which a 

 more extended knowledge might subsequently upset. There are 

 two or three very characteristic variations which commonly oc- 

 cur on our coast. These will be described as varieties of Asterias 

 rubens ; for until we can accurately fix a reliable and undeviating 

 standard of specific characters, it is surely best to allow a margin 

 for variation of species, which occurs to a greater or lesser de- 

 gree amongst most animals. Bearing upon the question of the 



* There may perhaps be a doubt about one of these species, Asterias hispida. 



