BREAKFAST-TABLE ZOOLOGY 13 



enable a man to discern, from a comparison of the lobster 

 alone with its entomostracan parasite, that they are alike 

 crustaceans, which is, nevertheless, known to be the case. 

 In a dishful of prawns it may often be noticed that one or 

 two of the finest have the head swollen on one side, as if 

 the creature were suffering from a face-ache. There is no 

 special reason to suppose that the prawn thus affected is 

 suffering any great inconvenience. It is merely lending the 

 shelter of its carapace to a family of isopod crustaceans. 

 Comfortably ensconced in the bulging cheek-piece will be 

 found a misshapen animal of no inconsiderable size, in 

 general laden with innumerable eggs, and accompanied by 

 a far smaller partner, the father of the brood, symmetrical 

 in form, and retaining some of the freedom of movement 

 which belongs to the young when first hatched, but which 

 the mother has entirely resigned. Thus the zoology of 

 the breakfast table will supply examples of three very dis- 

 tinct orders. These examples are none the less curious 

 because they happen to be common. Any one who is 

 content to examine them with care will thereby lay a 

 simple and solid foundation for all subsequent study in 

 the realm of carcinology. 



The novice, however, need not be dependent on the 

 fishmonger for specimens. In cellars, gardens, hedges 

 and ditches, under flat stones, in dry moss, among moist 

 dead leaves, in the loosened decaying bark of trees, crusta- 

 ceans are to be met with almost everywhere. These are 

 the so-called wood-lice, including those known by the 

 trivial names of Pill-bugs and Slaters, Millepedes, and 

 Carpenters. One species, small and white and slow in 

 movement, is frequently to be found in ants' nests, and 

 seemingly never elsewhere. All this set of animals, 

 though air-breathing and living on land and often possess- 

 ing great agility, belong to the Isopoda in common with 

 the marine species above mentioned that leads its apathetic 

 life within the carapace of the prawn. 



From almost every little brook and pond in England 

 the amphipod, Gammaras pulex, and the isopod, Asellus 

 aquaticus, may be fished without diflSculty and without 



