NIPHARGUS. 313 



obtained from artificially -excavated wells connected with 

 houses for domestic purposes. In some instances the 

 wells have been old, in others but recently dug.* In 

 their geological condition the habitats have been equally 

 various. At Corsham the well exists in the Oolite 

 formation, at Ringwood in chalk-flint gravel, at Manna- 

 mead in slate. f At Corsham and Mannamead they are 

 found on a hill, at Ringwood they lie low. 



The appearance of some of these animals in a well soon 

 after its being excavated, raises a question of considerable 

 interest. Thus they were found at Upper Clatford, near 

 Andover, and at Mannamead,J near Plymouth, but not a 

 trace of them was to be found in the surrounding streams ; 

 in fact, they perish in the light. It is impossible to regard 

 them as an extreme variety, or modification of our only 

 fresh-water Amphipod, Gammarus fluviatilis, since various 

 parts not only differ in form but some are altered in 

 character ; for example, the extraordinary elongation 

 and slenderness of one of the branches of each of the 



* By a misprint in the Catalogue of Amphipoda of the British Museum 

 (p. 177), the pump at Upper Clatford is said to have been very recently dry 

 instead of recently dug. The difference in the habits of the animal implied 

 in these two terms requires the correction of the error. 



t Shortly after the exhibition of the specimens from Maidenhead, at the 

 Linnaean Society, Mr. Edwin Lees informed us of the discovery by himself of 

 a specimen in water from the well of his own residence, in Cedar Terrace, 

 Henwick, Worcester. This well had been deepened in the preceding year into 

 the red marl, which is the formation under gravel. The animal had not been 

 previously seen, and only a single individual was observed. On the other 

 hand, the specimens captured by Mr. Herbert Mullins were obtained from a 

 well thirty feet deep, in an underground cellar, in the middle of the house at 

 Corsham, built about 1668, known as Lady Mary Hungerford's Charity : 

 the water is stated to be much impregnated with iron, and curdles with 

 soap. 



Mr. Hogan states that they are found at all seasons of the year, but are 

 most abundant towards the close of the autumn. 



+ Since this has been in the press we are informed by our friend, Mr. 

 Charles Stewart, that they exist very numerously in an old well at Hartly, 

 which is half-a-mile from Mannamead, but in the same geological formation. 



