THE SPIDER AND SHELL. 83 



the tail of this, a great number of transverse rows of aceta- 

 bula are to be seen even without the aid of a glass. My 

 friend, Dr. Bright, has another naked specimen in which the 

 same formation, which must very much assist the hold of the 

 Pagurus, is visible."* There is something so uncommon 

 and wonderful in this adoption of the shell of one animal by 

 another, to favour which even an anomalism of structure was 

 requisite, that the great Swammerdam, familiar as he was with 

 all the miraculous phenomena of insect life, could never 

 credit the history, believing that the lobster was the true 

 original tenant. "Hence it appears what an idle fable that 

 is which is etablished even amongst those who study shell- 

 fishes, when they shew some of the crab kind in their mu- 

 seums, adding at the same time, that they pass from one shell 

 to another, devour the animals that lived in those shells, and 

 keep them for their own habitations. They dignify them 

 with sounding names and additions, as soldiers, hermits, and 

 the like ; and thus, having no experience, they commit gross 

 errors, and deceive themselves as well as others with their 

 idle imaginations."-]- It is, however, the very reverse of an 

 idle fable ; and here allow me to add that I know of no one 

 fact which more directly negatives all the strange hypotheses 

 which have been of late years broached relative to the capa- 

 bilities of animals to alter their forms and go forward to per- 

 fectibility ; for, assuredly, no animal coated, as the lobster is, 

 with a crust fitted with the nicest adaptation would yearn to 

 free itself of this mail and expose its thin skin to the rude 

 elements ; or, having done this folly, would not, were it able, 

 by a continual desire and consequent reflux of its fluids, 

 regenerate its own crust rather than thrust its naked tail, 

 from race to race, into a shell which is comparatively a cum- 

 bersome appliance, and not more neatly fitted to its bulk 

 than were the boots of the heavy dragoon to the uncalfed 

 legs of the famous Goose Gibby ! 



The animal most nearly allied to the Hermit-lobster which 

 uses a somewhat similar device is a native species of spider, 

 whose operations I have had the pleasure of witnessing. 

 This insect lives habitually in and under water ; but having 

 really no fellowship with that element, in which it can neither 

 live nor breathe like aquatic animals, that it may pass its life 

 there in a dry comfortable manner, it appropriates to its use 

 the old shells of water-snails (Limnseus stagnalis). Entering 

 the shell, the spider closes the aperture with a web or cur- 

 tain of varnished silk, which repels the water and hinders its 



* Zool. Journ. iv. 207. t n° ok of Nature, 66. 



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