tlKKJIIT-CllABS.] 



MUSEUM OF ANIMATED NATURE. 



313 



To the terrestrial habits of these crabs many 

 writers have made express allusion. Sloane, speak- 

 intj of the " Sokiier," apparently Cenobita Diogenes, 

 says, '■ This small lobster or crab differs in very 

 little from the European soldier or hermit-crab. It 

 hath two large forked claws like those of an ordinary 

 lobster, one of which is bigger than the other, both 

 rounded, more tumid, less prickly, and of a paler 

 red than that of Europe. They fit themselves with 

 any shell they find empty, whether it be of the land 

 or sea, and cover themselves almost over in it, car- 

 rying it on their backs wherever they go, like a 

 snaii. It is not possible to believe how quick both 

 the land-crabs and these soldier-crabs will run upon 

 the least appearance of danger. Till they are 

 turned up nothing appears but a dead shell, the 

 mouth of which lies undermost, out of which some 

 little part of the crab appears after it is taken up." 

 ('Jamaica.') Sloane figures the crab in a species 

 of Helix, or land shell, and we believe that one of 

 these ciabs in a Helix was living some lime since in 

 the Gardens of the Zool. Soc. 



Catesby, in reference to the same species, which 

 he figures in the shell of Turbo Pica, states that 

 " they crawl very fast with their shell on their back, 

 «nd at the approach of danger withdraw themselves 

 within the shell, and, thrusting out the larger claw 

 in a defensive posture, will pinch very hard what- 

 ever molests them. They frequent most those parts 

 of sea-shores which are covered with trees and 

 shrubs producing various wild fiuits on which they 

 subsist ; though I have seen them feed on the frag- 

 ments of fish and other animal substances cast on 

 shore. They, being roasted in the shell, are 

 esteemed delicate. I do not remember to have 

 seen any of them go into the sea." {' Hist. Caro- 

 lina.') 



A writer in the old French Encyclopjedia, who 

 most probably takes his account from t)\i Tertre's 

 Voyage, says, "There are in the isles of America 

 Hermit-crabs, which are three or four inches in 

 length. It is asserted that this animal comes once 

 a year to the edge of the sea, to lay its eggs and 

 change the shell ; for it is alleged to quit the shell 

 in vihich it is lodged, because, having increased in 

 size during the year, it finds itself incommoded in 

 its old shell. It therefore comes to the shore and 

 seeks a new shell which may be convenient for it. 

 As soon as it meets with one, it comes out of the 

 old one and tries the new lodging ; and if that suits 

 it, it remains there, but it is often obliged to enter 

 many shells, before it finds one proportioned to it. 

 If it happens that two hermit-crabs stop before the 

 same shell, a dispute arises, and the weakest yields 

 to the strongest." 



Like all other Crustacea, the hermit-crabs increase 

 in size at the periods of exuviation, but whether 

 this process takes place in the old shell or in a 

 new one, or out of a shell altogether, we have 

 no information. Certain it is, however, that the 

 •hell is changed as the growth of the animal may 

 require. 



Referring to our pictorial specimens, Fig. 3197 

 represents the common hermit-crab (Pagurus 

 Bemhardus) of our coasts. The upper figure 

 exhibits the animal out of its shell ; a, the right 

 jaw-foot ; h, the animal in the shell. Of the 

 great numbers of these crabs which we have seen, 

 and of which several specimens are now be- 

 fore us, most have made the shell of the Whelk 

 Iheir habitation. The species of this form are very 

 numerous; from many others we select as examples 

 the Pagurus deformis, found on the shores of the 

 Isle of France and the Seychelles (Fig. 3198) ; and 

 the Pagurus Chilensis (Fig. 3199), a native of the 

 coasts of Chile. 



With respect to the allied genus Cenobita, the 

 generic characters are laid down as follows: — The 

 ocular peduncles are rather short, but large and 

 compressed, so as to be nearly lamellar ; the cornea 

 occupies the terminal and external portion. The 

 internal antennae, inserted a little behind the ex- 

 ternal ones, are extremely large ; their first joint, 

 large at the base and cylindrical, reaches beyond 

 the eyes, and has a second joint still longer ; the 

 third joint is rather longer than the second, and sup- 

 ports two terminal filaments, one of which is short 

 and sctiform, the other stout, rather long, and ob- 

 tuse. The external antennae are very much com- 

 pressed, their peduncle is long, but does not reach 

 the extremity of the second joint of the internal 

 antennae, and their palp is only represented by a 

 small rudimentary tubercle. The external jaw-feet 

 are pediform, short, nearly cylindrical, and devoid 

 of teeth toward their base. The anterior feet are 

 ■tout, unequal, and terminated by a short claw, 

 which ts compressed internally. The second and 

 third pair are large but present nothing remarkable ; 

 the fourth pair are nearly rudimentary, and their 

 last joint has the form of a small tubercle, scarcely 

 moveable ; the fifth pair are formed as in Pagurus, 

 except in the male, where their basilary joint pre- 

 sents a tubular prolongation more or less extended, 

 Vol.. II. 



at the extremity of which is the generative appa- 

 ratus. The abdomen is membranous and rolled 

 upon itself, as in the Faguri, but is shorter. In the 

 female it has, on the left side, three rather large 

 false oviferous feet fixed to the dorsal plates ; far- 

 tlier backward is a fourth horny plate without any 

 appendage. At the extremity of the abdomen is a 

 dorsal horny segment, with a median lamina on its 

 posterior border, and on each side an appendage, 

 that of the right side being much the smallest ; the 

 form of these appendages is the same as in the 

 Paguri. In the male all these abdominal appen- 

 dages, with the exception of the terminal pair, are 

 completely wanting; but dorsal horny plates indi- 

 cate the division of the abdomen into rings. 



Fig. 3200 represents the under surface of the 

 thorax of Cenobita. 



The Cenobiles are all natives of the warmer 

 regions ; we have already alluded to the Cenobita 

 Diogenes. It is represented at Fig. 3201 : a is the 

 animal partially out of shell, so as to show the 

 arrangement of the limbs, and of these the fourth 

 pair, with their file-like terminations for firm appli- 

 cation to the smooth columella, are very conspicuous; 

 b is the large claw ; e, Cenobite housed completely 

 within the shell, showing how the entrance is guarded 

 by the limbs, and especially by the great claw, 

 which acts as a sort of operculum, and is at the 

 same time ready for active service in case of emer- 

 gency. The shell in which the Cenobite is housed 

 is the Turbo Pica. The Cenobita Diogenes is a 

 native of the Antilles. 



From the genus Pagurus has been separated by 

 M. Milne Edwards a form to which he has given 

 the name of Cancellus, but of which little is known. 

 He himself, as he informs us, had only examined the 

 male of the species on which he founded the genus, 

 and of which it is the only ascertained example. 

 The abdomen, instead of being rolled upon itself and 

 terminating in a sort of shapeless tail, is perfectly 

 symmetrical ; the appendages of the penultimate 

 segment have the same form as in the Paguri, but 

 are similar on each side, and there is no other ap- 

 pendage adhering to the abdomen between this 

 segment and the thorax. Fig. 3202 represents the 

 Cancellus typhus. 



The following characters are enumerated by 

 Milne Edwards: — Ocular pedunclesslender, reaching 

 beyond the peduncle of the external antennae for 

 nearly one-half of their length, but nevertheless 

 shorter than the anterior border of the carapace ; 

 cornea transparent, very small, and without any 

 notch on its superior border. External antennae 

 very short, hardly more than twice as long as the 

 ocular peduncles. Anterior feet equal, and de- 

 pressed above ; on the upper edge of the claw- 

 joint a dentilated crest, which is united to a 

 rounded longitudinal elevation on the external sur- 

 face, so as to form a pyramid of three faces on the 

 carpus; external surface of the claw-joint a little 

 warty ; pincers very short. Second pair of feet 

 much stouter and longer than the third, and fur- 

 nished with a crest which extends from the middle 

 of the third joint to their extremity, in describing a 

 regular curve, the convexity of which is outwards ; 

 the upper extremity of this crest is elevated, like 

 that of the anterior feet, pyramidically, and corre- 

 sponds exactly to the extremity of the ocular pe- 

 duncles, when the feet are directed forwards. Tarsi 

 very short and rather stout. Third pair of feet much 

 compressed. Basilary joint of the posterior feet 

 large and squamiform. Abdomen of the male short, 

 large, furnished above with very narrow transverse 

 plates, which have no appendages, and terminated 

 by a pair of appendages as in the other Pagurians, 

 but symmetrical, and by a median lamina equally 

 symmetrical. 



Leaving the Pagurians, we immediately advance 

 to a very singular crustacean, the type of the genus 

 Birgus, remarkable for its manners and general 

 habits. 



The characters of the genus Birgo are detailed 

 nearly as follows by M. Milne Edwards ('Hist. 

 Nat. des Crustaccs'). The carapace is terminated 

 anteriorly by a projecting ro.strum, and is of con- 

 siderable extent, forming a convex shield over the 

 branchiae on each side. The ocular peduncles are 

 stout, rounded, and of moderate length. The in- 

 ternal antennae have the same conformation as in 

 the Cenobites, except that their basilary joint is 

 still more elongated. The disposition of the exter- 

 nal antennae and of the external jaw-feet is also 

 entirely the same as in the last-named Pagurians. 

 The anterior feet are stout, rounded, and of mode- 

 rate length ; the two succeeding pairs are terminated 

 by a stout cylindrical joint ; and the fourth pair, 

 which are shorter than the preceding, but not ele- 

 vated above them, are provided with a cheliform 

 hand, the two fingers of which are long and cylin- 

 drical ; the posterior feet, which are very short and 

 cylindrical, are elevated under the lateral parts of the 

 carapace, and terminated by a very obtuse rudi- 

 mentary pincer. The abdomen is very large, and 



covered above by a small horny band, followed by 

 four great corneo-calcareous plates, which occupy 

 its whole width, and over-ride each other, as in the 

 Macrurous Crustaceans. On each side of these 

 great segments are to be seen one or two horny 

 pieces. In the female, the three first of these 

 segments, that is to say, the second, third, and fourth 

 rings, have on each side a great false foot formed 

 by a small basilary piece and two great narrow and 

 ciliated appendages ; those members are wanting 

 on the right side, and in the male no trace of them 

 is perceptible. The whole of the inferior surface 

 of the abdomen is membranous, except that to- 

 wards its posterior part may be seen a small 

 quadrilateral plate, which gives attachment to a 

 second projecting plate, and has on each side an 

 abdominal rudimentary false foot, composed of a 

 basilary piece and two moveable tubercles, which 

 recal the disposition of the appendages of the sixth 

 abdominal ring of the Paguri, biit which is sym- 

 metrical on both sides of the body. The terminal 

 plate is rounded at the end, and represents the 

 seventh abdominal ring. 



The respiratory apparatus in Birgus presents very 

 remarkable peculiarities of structure. The branchiae 

 are fourteen in number on each side of the body, 

 and are fixed by a peduncle situated towards the 

 middle of their internal surface. The respiratory 

 cavity is very large, and the branchiae only fill the 

 tenth part of it; its vault is carpeted below by a 

 delicate and epidermic membrane; but this soon 

 disappears and leaves naked the skin, which is con- 

 tinued with that membrane, and covered by a mul- 

 titude of vascular vegetations. 



The Birgus Latro (Fig. 3203), Purse-crab, or Rob- 

 ber crab (Pagurus Latro, Fabr. ; Cancer crummen- 

 tatus, Rumpliius), is a native of Amboyna and the 

 neighbouring islands, and attains to a considerable 

 size. In its habits it is terrestrial, inhabiting the 

 fissures of rocks by day, and coming forth at night 

 to seek for its food upon the beach. It appears to 

 be frugivorous as well as carnivorous, and is re- 

 ported to climb the cocoa-nut trees for the purpose 

 of obtaining the fruit. To this account Linnaeus, 

 Heibst, and Cuvier refer, and it is no doubt based 

 upon truth. The following extract from the 'Pro- 

 ceeds. Zool. Soc' 1832, p. 17, may not be uninter- 

 esting : — " A specimen was exhibited of Birgus 

 Latro, which had been presented to the. Society by 

 Mr. J. P. Vaughan, and Mr. Owen referred to the 

 curious statement of Herbst that this crab climbs 

 trees for the purpose of stealing cocoa-nuts ; a state- 

 ment partially confirmed by the fact, recorded by 

 MM. Quoy and Gaimard, that individuals of this 

 species were fed by them for many months on co- 

 coa-nuts alone. A more ample confirmation, he 

 remarked, was furnished by some observations com- 

 municated to him by Mr. Cuming, whose fine collec- 

 tion contained several specimens obtained in the 

 islands of the South Pacific Ocean. They climb, 

 Mr. Cuming slates, a species of palm (Pandanus 

 odoratissimus), and eat a small kind of cocoa-nut 

 that grows thereon. They live at the roots of the 

 trees, and not in holes in the rocks, and are a favour- 

 ite food of the natives." To give an idea of the 

 kind of palm these crabs are in the habit of climb- 

 ing, we represent, at Fig. 3204, one of the Pandanus 

 tribe, Freycinetia imbricata, with its fruit. 



Mr. Cuming observed these crabs in great abund- 

 ance at Lord Hood's Island, in the Pacific. When 

 he met them in his road, they set themselves up in 

 a threatening attitude, and then retreated backwards, 

 making both at first and afterwards a great snap- 

 ping with their pincers. Linnaeus confounded this 

 species with the land-crabs (Gecarcinus) of the 

 West Indies, called during their moult " Crabes 

 boursiers." 



We now arrive at a small group, termed Porcel- 

 lanians, consisting of Crustacea which have the port 

 and aspect of the Brachyura, but in which the ab- 

 domen ends in a fan-like caudal fin : the abdomen 

 itself is wide, but lamellar, and bent against the 

 sternum. Fig;. 3205 represents Porcellana platyche- 

 les ; a, the tail unfolded. This crab is of small size, 

 being scarcely three-quarters of an inch in length. 

 It is a native of the casts of France and England. 



Another genus belonging to this tribe i.s j^glea, 

 of which the y^iglea laevis from the coast of Chile 

 (Fig. 3206) is an example. It is about two inches 

 in length. 



A tribe closely allied to the Porcellanians is re- 

 presented by the genus Galathea. The carapace is 

 depressed and wide ; the anterior limbs are large, 

 the fifth pair very slender ; the abdomen nearly as 

 wide as the thaax and longer, and terminates in a 

 large fan-shaped lamelliforra fan; false feet, five 

 pairs in the male. 



The Galathea strigosa (Fig. 3207), which we se- 

 lect as an example, is about five inches in length; 

 its colour is reddish, with lines of blue on the cara- 

 pace. The limbs are strongly spined, as is also the 

 margin of the carapace. This species inhabits tlie 

 Mediterranean and the Ocean. 



2S2 



