GECARCINUS. 



GECARCINUS. 



934, 



Audouiu and Milne-Edwards some years ago, wherein the authors 

 show that in all the Crustacea the branchiae are fitted to perform the 

 functions of respiratory organs in the air as well as in the water ; 

 that the more or less rapid death of the aquatic species, when exposed 

 to the air, depends upon various causes, of which one of the most 

 direct is the evaporation from the branchiae, which produces their 

 desiccation ; that consequently one of the conditions necessary to 

 the support of life in animals which have branchiso, and live in the 

 air, is the having these organs defended against desiccation ; and 

 lastly, that these dispositions actually occur in the Land-Crabs, 

 which all possess various organs destined for absorbing and keeping 

 in reserve the quantity of moisture necessary for maintaining a 

 suitable degree of moisture in the branchiae. [CRUSTACEA.] 



The Land-Crabs, or Gecarcinians, inhabit the warm countries of 

 the New and Old World, and Australasia ; but as far as observation 

 has hitherto gone, America and its islands seem to be the places 

 where the form is most highly and most numerously developed. 

 Almost every writer on the Natural History of the countries last 

 mentioned treats largely on the habits of these creatures ; and in the 

 works of Rochefort (' Histoire Naturelle des Antilles '), De Feuill<5e 

 (' Observations faites sur les Cotes d'Amerique '), De Labat (' Nouveau 

 Voyage aux Isles d'Amerique'), Sloane (' Natural History of Jamaica'), 

 Browne (' Civil and Natural History of Jamaica '), Hughes (' Natural 

 History of Barbadoes ), Catesby (' Natural History of Carolina'), &c., 

 Ac., will be found details more or less ample, and highly interesting, 

 of their manners ; though most of the writers do not determine the 

 species sufficiently to enable us to judge of what particular Land-Crab 

 they are writing. All these authors will however well repay the 

 trouble of consulting them. 



Latreille sums up what he considers the credible parts of these nar- 

 ratives thus : " The crabs pass the greatest part of their life on land, 

 hiding themselves in holes, and not coming forth till evening. Some 

 keep about cemeteries. Once a year, when they would lay their eggs, 

 they assemble in numerous bauds, and move in the shortest direction 

 to the sea, without caring for any obstacles. After they have finished 

 their deposit they return much weakened. It is said that they block 

 up their burrows during their moult ; and while they are undergoing 

 this operation, and are still soft, they are called Boursiers (Purse- 

 Crabs) [Bilious], and their flesh is then much esteemed, although it is 

 sometimes poisonous. This quality is attributed to the fruit of the 

 mauchineel, of which the people think, falsely perhaps, that the crabs 

 have eaten." 



With regard to the alleged want of foundation for the story of the 

 Land-Crabs being sometimes poisonous, in consequence of what they 

 have eaten, there are so many testimonies to the fact, that it will be 

 a fault on the right side to be cautious. Thus Sloane, who praises 

 (as who does not ?) their delicacy of taste, says : " They are thought 

 to be poysonous when they feed on the Mansanilla-tree leaves or fruit, 

 which I suppose may come from some of it sticking to their chaps, or 

 lying undigested in their stomachs, which are not separated before 

 eating." Catesby writes : " Some are black, some yellow, some red, 

 and others variegated with red, white, and yellow mixed. Some of 

 these, as well as of the fish of this country, are poisonous ; of which 

 several people have died, particularly of the black kind : the light- 

 coloured are reckoned best, and when full in flesh are very well tasted. 

 In some of the sugar islands they are eat without danger, and are no 

 small help to the negro slaves, who on many of the islands would fare 

 very ill without them. They feed on vegetables." Hughes, speaking 

 of the ' large white land-crab,' and its feeding on grass, &c., remarks : 

 " They likewise often feed upon manchineel apples, as well as upon 

 the leaves or berries of poison-trees. At such times they are dangerous 

 to be eaten, unless very great care be taken to wash the fat, as well as 

 the other meat on the inside, with lime-juice and water." He says the 

 same in effect of ' the Mulatto Crab.' 



M. Milne-Edwards thus gives his summary : " The greater number 

 ordinarily haunt humid places, and hide themselves in holes which 

 they excavate in the earth, but the localities preferred by them vary 

 with the species. Some live in the low and marshy lands near the 

 sea, others on the wooded hills far from the shore ; and at certain 

 epochs, these last quit their habitual dwelling to go to the sea. It is 

 even reported that then these Crustaceans unite in great bands, and 

 thus make very long journeys without suffering themselves to be 

 stopped by any obstacle, and laying waste everything in their route. 

 Their principal food consists of vegetable substances, and they are 

 nocturnal or crepuscular in their habits. It is more particularly in 

 the rainy season that they quit their burrows, and they run with great 

 rapidity. It would appear that it is at the time of laying that they 

 go to the sea and there deposit their eggs, but we know of no decidedly 

 positive observation on this point. During their moult they remain 

 hidden in their burrows." (' Hist. Nat. des Crustaces.') 



We select Browne's account of the Black or Mountain Crab (Cancer 

 ruricola, Linn.), because he resided many years in the island of 

 Jamaica, and seems to have lost no opportunity of making personal 

 observations : " These creatures are very numerous in some parts of 

 Jamaica, as well as in the neighbouring islands, and on the coast of 

 the main continent. They are generally of a dark purple colour, but 

 this often varies, and you frequently find them spotted, or entirely of 

 another hue. They live chiefly on dry land, and at a considerable 



distance from the sea, which however they visit once a year to wash 

 off their spawn, and afterwards return to the woods and higher lands, 

 where they continue for the remaining part of the season ; nor do the 

 young ones ever fail to follow them as soon as they are able to crawl. 

 The old crabs generally regain their habitations iu the mountains, 

 which are seldom within less than a mile, and not often above three 

 miles from the shore, by the latter end of June, and then provide 

 themselves with convenient burrows, in which they pass the greatest 

 part of the day, going out only at night to feed. In December and 

 January they begin to be in spawn, and are then very fat and delicate, 

 but continue to grow richer until the mouth of May, which is the 

 season for them to wash off their eggs. They begin to move down in 

 February, and are very much abroad in March and April, which seems 

 to be the time for the impregnation of their eggs, being then frequently 

 found fixed together ; but the males about this time begin to lose 

 their flavour and the richness of their juices. The eggs are discharged 

 from the body through two small round holes situated at the sides, 

 and about the middle of the under shell : these are ouly large enough 

 to admit one at a time ; and as' they pass they are entangled in the 

 branched capillaments, with which the under side of the apron is 

 copiously supplied, to which they stick by the means of their proper 

 gluten, until the creatures reach the surf, where they wash them all 

 off, and then they begin to return back again to the mountains. It is 

 remarkable that the bag or stomach of this creature changes its juices 

 with the state of the body ; and while poor is full of a black, bitter, 

 disagreeable fluid, which diminishes as it fattens, and at length acquires 

 a delicate rich flavour. About the month of July or August the crabs 

 fatten again, and prepare for mouldering, filling up their burrows 

 with dry grass, leaves, and abundance of other materials : when the 

 proper period comes each retires to his hole, shuts up the passage, 

 and remains quite inactive until he gets rid of his old shell and is fully 

 provided with a new one. How long they continue in this state is 

 uncertain ; but the shell is observed to burst both at the back and 

 sides to give a passage to the body, and it extracts its limbs from all 

 the other parts gradually afterward. At this time the fish is in the 

 richest state, and covered ouly with a tender membranous skin, 

 variegated with a multitude of reddish veins, but this hardens gradu- 

 ally after, and becomes soon a perfect shell like the former : it is 

 however remarkable that during this change there are some stony 

 concretions always formed in the bag, which waste and dissolve gradu- 

 ally as the creature forms and perfects its new crust. A wonderful 

 mechanism ! This crab runs very fast, and always endeavours to get 

 into some hole or crevice on the approach of danger ; nor does it 

 wholly depend on its art and swiftness, for while it retreats it keeps 

 both claws expanded, ready to catch the offender if he should come 

 within its reach, and if it succeeds on these occasions it commonly 

 throws off the claw, which continues to squeeze with iucredible force 

 for near a minute after ; while he, regardless of the loss, endeavours 

 to make his escape and to gain a more secure or a more lonely covert, 

 contented to renew his limb with his coat at the ensuing change ; nor 

 would it grudge to lose mauy of the others to preserve the trunk 

 entire, though each comes off with more labour and reluctance as their 

 numbers lessen." 



Thus much of the habits of the Land-Crabs of the New World. 

 The late Bishop Heber, in his ' Narrative ' gives an account of some 

 Land-Crabs in India, living at a great distance from the sea, and 

 obstructed by great obstacles in their passage to it. " The plain of 

 Poonah," writes the bishop, " is very bare of trees, and though there 

 are some gardens immediately around the city, yet as both these and 

 the city itself lie in a small hollow on the banks of the river Moola, 

 they are not sufficiently conspicuous to interrupt the general character 

 of nakedness in the picture, any more than the few young trees and 

 ornamented shrubs with which the bungalows of the cantonment are 

 intermingled. The principal and most pleasing feature is a small 

 insulated hill immediately over the town, with a temple of the goddess 

 Parvati on its summit, and a large tank (which, when I saw it, was 

 nearly dry) at its base. All the grass-land round this tank, and 

 generally through the Deckan, swarms with a small land-crab, which 

 burrows in the ground, and runs with considerable swiftness, even 

 when encumbered with a bundle of food almost as big as itself. This 

 food is grass, or the green stalks of rice, and it is amusing to see 

 them sitting as it were upright, to cut their hay with their sharp 

 pincers, then waddling off with the sheaf to their holes as quickly as 

 their sidelong pace will carry them." Upon this passage Mr. Broderip 

 observes, that when we call to mind the position of Poonah, and read 

 of the neighbouring river and tank, we may feel inclined to ask 

 whether the river or the tank might not be the scene of ovipositing ; 

 and, he adds, that it is not improbable that there may be a race of 

 land-crabs appropriated to continental or even insular situations out 

 of reach of the ocean, and that fresh water may be as necessary to 

 their reproduction as sea-water is to the land-crabs of the West 

 Indies. Such a supposition, he thinks, is in unison with the bounti- 

 ful provisions of nature for the general diffusion of animal life. 

 (' Zool. Journal,' vol. iv.) 



Mr. Westwood in his interesting paper ' On the supposed Existence 

 of Metamorphoses in the Crustacea' ('Phil. Trans.,' 1835), notices the 

 abdomens of several female crabs having the interior surface covered 

 with hundreds of eggs or newly-hatched young, which were in the 



