HKHM IT-CRAB 



IIKIt.MI.'S 



687 



Hermit-crab, a name applied to the members 

 of a family of crustaceans ( Pagurid;e), notable for 

 their liubit of sheltering themselves in 



shells, and for tin- soft skinned itml generally un- 

 >\ m metrical tail, probably in part tin- caiiHe and 

 in part tlit! consequence of this curious custom. 

 The eves arc Wine on long stalks ; the great clawa 

 are very large ami generally uncciual, one being 

 n-i'il in clo-e tin' entrance of tin- shell into which 

 tin- liciiuit can wholly retract himself; the ab- 

 dominal appendages arc practically aborted, with 

 tin- exception of those at the tip of the tail, which 

 hold so firmly on to the spin- of the inhabited 

 shell that it is dillicult to pull out the crab un- 

 broken. There are a great many different kinds of 

 hermit crahs. and these utilise many forms of gas- 

 tempod shell, not always keeping constant to one 

 type of house. The commonest species (Paym-nx 

 or Knnaijiirit.'i ln-niluiriliix) is usually found tenant- 

 ing the shells of the whelk (Buccinum); while 



Common Hermit-crab shifting from one whelk shell 

 to another. 



another very common species (P. or E. prideauxii) 

 may be found inside shells of Fusus, Murex, Can- 

 cellaria, Turbo, Buccinum, &c., and is also very 

 interesting as an illustration of partnership or Com- 

 mensalism (q.v. ) with a species of sea-anemone 

 which forms a cloak rouna the shell. It masks 

 the hermit-crab, and may also be useful on account 

 of its stinging-cells, while the hermit-crab repays 

 the anemone by carrying it about, and doubtless also 

 with debris of food (for illustration, see ANEMONE). 

 This habit of helpful partnership has been observed 

 even in Pagurus abyssorum from a depth of 

 3000 fathoms. As hermit-crabs grow they have 

 not only to cast their own armature in the usual 

 crustacean fashion, but they must periodically 

 shift to a successively larger and larger house. In 

 looking out for a new shell to tenant hermit-crabs 

 are naturally in a hurry, being then in a position 

 of defencelessness unusual for them ; ana it has 

 been observed that they do not always seek for an 

 empty mollusc shell, but may evict the rightful 

 owner of one which strikes their fancy. The 

 common hermit-crabs feed on molluscs ;UK! animal 

 debris. They are most interesting inmates of 

 aquaria, but their voracity is very apt to reduce 

 the population. 



Some of the deep-sea hermit-crabs, brought up 

 by the Challenger, Blake, and other explorations, 

 are of much interest, especially perhaps inasmuch 

 as several retain the symmetry which the more 

 familiar forms tenanting spiral shells have lost. 

 As such shells are rarities at the bottom of the 



living in straight 



deep sea. some of the hermit* retain the doubtleM 



original free lite. Such in Tylaxpit anonmla, from 



the Honth Pacific at a depth of 2375 fathom*, which 



IKI- a very much shortened abdomen, with distinct 



--mi-Hi -, however, and well -developed symmetrical 



appendage*. From the West Indies the J',lnl.e 



Downed /'<//<//.* iniimxizi 



tulies of compacted sand, 



and quite symmetrical. 



Even more interesting is the 



By m metrical XylojMiqurut 



rectus, living at depths of 



300 to 400 fathoms, in open 



tubes of wood or bamboo- 



st em. into which the animal 



retreats head foremost, and 



guards the opening with 



linn plates on the end of 



the tail. 



The members of the genus 

 Cwnohita, from the shores 

 of the Indian Ocean and 

 other warm seas, live in all 

 sorts of houses, including 

 the shells of marine gastero- 

 pods (Murex, Purpura, &c.), 

 of landsnails, of sea-urchins, 

 or even nuts. One species, Xylopagurus rectut in its 

 C. rugosa, is famous for its oase () and free (&) 

 fondness for cocoa-nuts, and 



for its excursions ashore. In another genus, the 

 robber hermit-crab (Birgus latro), from the East 

 Indies, lives in holes in the earth under trees, 

 has an almost lung-like modification of the gill- 

 cavity for breathing air directly, yet visits the sea 

 periodically by night. It feeds on cocoa-nuts, 

 though it does not climb for them, ami is itself 

 eaten in Amboyna and elsewhere. Darwin has 

 graphically described how it tears the husk from 

 the cocoa-nuts, and hammers on the round de- 

 pressions at one end until entrance is effected. 

 Out of a biscuit-box, the lid of which was fastened 

 down with wire, a robber-crab made its escape, 

 actually punching holes in the tin and turning 

 down the edges. 



See COMMENSALISM, CRAB, CRUSTACEA ; J. R. Hen- 

 derson, Challenf/er Report on Anomura ; Agassiz, Voyage 

 of the Blake ; Marshall, Das Tiefsee und ihr Leben (Leip. 

 1888) ; and Darwin, Voyage of Vie Beayle (Lond. 1845). 



Hermodactyl. See COLCHICUM. 



Herinon, MOUNT (now Jebel-es-Sheikh), 9150 

 feet high, is the culminating point of the Anti- 

 Libanus range. See LEBANON. 



Hermopolis Alagiia, an ancient town of 

 Egypt, situated on the Nile, on the border of the 

 Thebaid, and near the frontier line of upper and 

 middle Egypt. Thanks to its position, Hermopolis 

 grew to be a place of great importance, ranking 

 next after Thebes. It had a celebrated temple 

 sacred to Thoth, the ibis-headed god of letters, of 

 which the portico alone is all that now remains. 

 On the opposite or right bank of the Nile was 

 Antinoopolis, where the dead of Hermopolis were 

 taken for burial. The modern name of Hermopolis 

 is Ashmun or Eshmoon. 



Heriliosillo, capital of the Mexican state of 

 Sonora, stands in a fertile plain on the Rio Sonora, 

 50 miles by rail N. of the port of Guaymas. It has 

 a mint and other government buildings, a bank of 

 issue, sawmills, distilleries, and shoe and furniture 

 factories, and a large export trade in wheat and 

 wine. Pop. 15,000. 



Herinoupolis. See SYRA. 

 II (Tin n s. a river of Asia Minor, flowing through 

 the plain of Sardis, and falling into the Gulf of 



Smyrna. 



