A HISTORY OF NOTTINGHAMSHIRE 



in damp moss travelled first to Tunbridge Wells, and were forwarded 

 thence to West Baling, having been in close confinement for about forty- 

 eight hours. Nevertheless, they arrived in a quite lively condition, and 

 one of the four, a female, survived to accomplish another postal journey 

 and to spend several months at Tunbridge Wells apparently much to its 

 own satisfaction. During this period it occupied a glass bowl 8J inches 

 in diameter by 3i inches deep. This was supplied with a layer of mud 

 at the bottom for the tenant to burrow in, with two or three rough 

 stones to assist it if necessary in sloughing its coat, with the moss in 

 which it had travelled from its native cascade, with some fresh Anacharis 

 alsinastrum and other pond weeds ; and, lastly, with water to the depth of 

 an inch or a little more. For food it was at first provided with sessile- 

 eyed crustaceans, water boatmen, and other experiments in aquatic pro- 

 vender ; but in the course of the winter it was found more convenient to 

 feed it on earthworms. These it did not attempt to kill, but it appeared to 

 eat them with much satisfaction when they had been converted into meat. 

 It soon ceased to show any sort of timidity or shyness, and would raise 

 itself out of the water when approached, as if courting society. It never 

 made any visible attempt to leave the bowl, yet one morning it was found 

 on the floor, having apparently effected its escape and fallen from a height 

 of 14 inches without injury. A considerable time after this escapade, 

 and without having shed its skin, it eventually met its death on 13 May, 

 1904. Though this catastrophe happened during my own absence from 

 home, it need not be assumed that the creature died of grief. It is more 

 likely to have succumbed to an abrupt rise of temperature which then 

 occurred. Of the four specimens from Shireoaks Park, the larger pair 

 were three inches long, the smaller about two inches, in each case the 

 male and female being approximately equal. I have specimens from 

 Oxfordshire far more bulky, and over four inches in length. 



The sessile-eyed Malacostraca are represented in our inland waters by plenty of individuals 

 but very few species. Of the Amphipoda only one species, the common Gammarus pulex 

 (Linn.), has hitherto been recorded for this county. According to Professor Carr it ' occurs 

 abundantly everywhere in streams and ponds.' * This little shrimp is under an inch in length. ' 

 A crayfish of small dimensions would outweigh a hundred of the Gammarus. Any near 

 relationship between the two could scarcely be suspected on a cursory inspection. Nevertheless 

 the structure in both is essentially the same, although in the smaller animal it is in some 

 respects simpler, and, on the hypothesis of a common origin, might be thought to show fewer 

 modifications of the ancestral form. The difference in appearance might be compared with that 

 which exists between a thin boy in an Eton jacket and a portly man in a frock coat. It 

 depends essentially on the covering capacity of the carapace. This great shield in the crayfish 

 extends over the segment which carries the eyes and over thirteen other appendage-bearing 

 segments, which are all except the last in complete coalescence. But in Gammarus the coat 

 or carapace is so short that seven of this number are left uncovered and remain movably 

 articulated, like the seven following segments, which in both species alike constitute the pleon 

 or tail. To several appendages of those uncovered middle segments in the amphipod it will be 

 found that little sacs or vesicles are attached. These simple bag-like organs are the gills 

 or branchiae. In the crayfish the corresponding organs are divided up into numerous filaments, 

 exposing a much larger surface for the oxygenation of the blood in the course of its circulation. 

 Moreover, they are attached to a greater number of appendages, and instead of hanging freely 

 in the water, they are efficiently sheltered in a pair of branchial chambers, formed by the 



1 Op. cit, p. i. 

 144 



