340 Rev. T. R. R. Stebbing on Amphipodons Crustaceans. 



wrist has the hinder margin smootli, and is shorter than the 

 metacarpus, but is otherwise like it. The hand has spines 

 along the front margin, and a little tuft of hairs in the centre 

 of the margin behind, with some long ones projecting from 

 its point of junction with the finger. 



In H. LuhbocMana all these joints are stout. The meta- 

 carpus has two short spines standing stiffly out from its hinder 

 margin, and an inconspicuous one at the distal end, with two 

 very small pairs on the front margin. The wrist has two 

 pairs of short spines in front. The hand behind is continu- 

 ously curved and free from hairs or spines; its anterior margin 

 presents three sections — the first armed at the end furthest 

 from the wrist with a stout spine, this spine terminating in a 

 very minute hook ; the next section, besides two or three small 

 setge, carries that which is the most striking feature of this 

 species, a spine twice as long and twice as thick as the one 

 just mentioned, conspicuously hooked at the end, and serrated 

 along the lower margin ; it is movable, and can be brought into 

 contact with the large scimitar-like serrated finger ; near to 

 the junction of the hand and finger there is another spine, a 

 copy of the preceding one on a far smaller scale. 



It was noticed above that HyaJe Nilssoni has and exercises 

 great powers of leaping ; and we might wonder that IlyaJe 

 Lnhhochiana^ so similar in size and general structure, living 

 apparently in precisely the same environment, should neglect 

 or not possess so effective a resource for escaping from enemies. 

 But a consideration of the spines just described seems to in- 

 dicate that its safety is consulted by holding fast, while its 

 neighbours have recourse to the opposite expedient of sud- 

 denly skipping away. Of the three spines in question, the 

 central and largest would seem a development very difficult 

 to explain, if its two companions did not show us actual gra- 

 dations leading up to it from the ordinary simple spine — those 

 at the extremity of the wrist supplying yet another inter- 

 mediate step, and making it clear by one more example how 

 small the changes may be by which very considerable and 

 sti-iking revolutions may be produced in the forms and habits 

 of living creatures. With Hyale Nilssoni one might easily 

 be tempted to make separate species for the elder and younger 

 forms, did not a well-graduated intermediate series give very 

 fair evidence of the family tie bet\veen them. 



Anonyx serratus, Boeck. 



Among the species of Anonyx deserihed by Messrs. Bate 

 and Westwood, two will be found closely resembling one 



