NIPHARGUS FONTANUS. 321 



to the Hope Collection at Oxford) in a similar well about 

 two hundred years old at Corsham in Wiltshire, as above- 

 mentioned. Mr. Lubbock has also taken it in a well at 

 High Elms in Kent. 



Through the kindness of Mr. Hogan, who sent us 

 living specimens, we were enabled to watch it alive for 

 many weeks. There appeared little in the habits of 

 this creature that distinguished it from the common 

 Gammarus of our fresh-water streams, for even its 

 desire to seek the darkness (and Mr. Hogan informs 

 us that it soon dies if exposed to the light) is but an 

 exaggeration of the habits of these Crustacea to hide 

 themselves beneath rocks, stones, and weed. 



We observed, when watching the animal very closely, 

 that the strong spines, which define the limits of the 

 palm on the first two pairs of hands, are moveable. 



The colour of the animal is of a milky hue, but not 

 quite white. The eyes are brimstone yellow, small, and 

 irregularly formed. 



If we are correct in following Schiodte in assuming 

 that the difference of length in the posterior caudal 

 appendages of certain specimens indicate sexual dis- 

 tinction, it is at least a curious circumstance that the 

 long-tailed form was not found associated at Corsham 

 and Ringvvood ; the males, if such they were, being 

 found at Corsham in Wiltshire,* and tlie females taken 

 at Ringwood in Hampshire. 



In the " Catalogue of Amphipoda of the British 

 Museum," we have stated that the males also differ 

 from the females in having the second pair of hands less 

 tapering and graceful; but we find that it is the females 



* Among the specimens presented by Mr. Mullins to the Hope Collection, 

 is a female with the terminal segments as represented in our figure u z. 



Y 



