234 



Marvels of the Universe 





IHE DOWN^ HERMll AND ITS AUGER-SHELL HOUSE. 



The Downy Hermit is a small, deep-water crab. The Auger-shell it has selected for a house is inainly covered by a 

 zoophyte which builds hard spines, and these help to protect the Hermit from being eaten by fishes. There are also the stony 

 tubes of certain sea-worms upon the shell, but their presence is probably accidental. 



this was not possible at the time ; but the attempt has been made by the author to reconstruct 

 the conditions with one of the actual crabs concerned. How long they had been in residence when 

 my attention was called to them is not known, but the fact that the Acorn-barnacles were so fully 

 developed is proof that they had been there some time. It is worthy of note that the anemone 

 ordinarily found wrapping the house of Prideaux's Hermit must secrete some acid, for I have ob- 

 tained numerous examples in which the hard limy material of the shell had been dissolved away, 

 and only the animal matter was left, like layers of tissue paper, but retaining the shell form. 



A smaller species from deeper water is the Downy Hermit, of which a photograph is given, 

 living in the large Auger-shell, which is here encrusted with the spine-like bases of polyps, similar to 

 those described as lining the mouth of the Common Hermit's borrowed shell, and which is shown 

 on page 233. It is as often coated bj' a small species of compound sea-anemone, which dissolves 

 away the Auger-shell, but continues its shape, so that the Hermit's cell becomes an entirely living 

 one. Several of these smaller species of Hermits might be mistaken at first sight for young examples 

 of the Common Hermit, but that they occur in deeper water. Another of these, shown in a photo- 

 graph on page 232, induces a little sponge to cover its hinder parts, and the sponge constantly 

 growing does away with the necessity for the crab changing its home. Yet another deep-water 

 species — the Hairy-handed Hermit — is covered by a sea-anemone, which has never been found 

 growing apart from the crab, and the crab has never been found apart from the anemone. This is 

 one of the most perfect forms of animal comradeship known. 



The examples cited — and they might be increased in number — are all drawn from British waters, 

 but all over the world the race of Hermit Crabs exhibits the same characteristics. Whether it was that 

 Nature was niggardly towards the first of the family and omitted to provide their hinder parts with 

 the shelly covering proper to crabs, or that the founder of the dynasty took to thrusting this part 

 into shells and set a fashion that has led bv disuse to the absence of crab-shell, must remain for the 



