Oct. 5, 1888.] 



SCIENTIFIC NEWS. 



36: 



Natural Wi$m£* 



THE CRUSTACEA OF THE SEA-BOTTOM. 

 M. Fourques gives in Cosmos an account of a very 

 strange crab dredged up during the expedition of the 

 Talisman, from a depth exceeding 2,000 fathoms. 

 The bottom of the sea was for a long time re- 

 garded as uninhabited. The operations required in the 

 Mediterranean in 188 1 for re-uniting a broken telegraph 

 cable, immersed at the depth of 1,000 fathoms, revealed 

 to the learned world, to its surprise, that at such depths 

 there existed living beings, in a darkness incompatible 

 with vegetable life, and at a pressure which seemed 

 opposed to all the working of the processes of 

 the animal world. Scientific expeditions were organ- 

 ised, and savants set out on vessels whose names 

 have become historical. The Challenger, the Talis- 

 man, and the Travaillcur carried out soundings at 

 various depths, and a totally novel fauna was de- 

 scribed and studied. Several remarkable fishes have 



larval forms were long considered as forming not merely 

 distinct genera but even families. Such are the Zoeae, 

 the larvae of the crabs, and Phyllosoma, the larvae of the 

 shrimps. 



These animals are encased in a thick calcareous shell, 

 often armed with long, sharp spines. Their senses are 

 highly developed. At the anterior part of the body they 

 are provided with two pairs of antennas, the organs of 

 hearing and smelling. 



In some species, however, the organs of hearing are 

 lodged at the posterior extremity of the body, under the 

 caudal plate. The organs of touch are very fine and 

 numerous hairs are situated around the mouth. The eyes 

 are sometimes fixed on stalks, and sometimes sessile. 

 There are, indeed, few species subject to so many 

 variations as the Crustacea. No fewer than 5,500 living 

 species are known, divided into ten orders, some of which 

 live as parasites upon fishes and are deprived of eyes, 

 and resemble worms in their appearance. Several in- 

 habit the bottom of the sea. During the expedition of 

 the Talisman, M, Filhol, one of the naturalists who took 



Lithodes Ferox : a Crustacean found at a Depth of 13,000 feet. 



been described which live at depths a thousand 

 fathoms below the surface. These fishes do not 

 differ in an essential manner from those of the pelagic 

 fauna. The same species, or closely allied species, are 

 met with at different depths. Their organs, however, 

 present certain modifications imposed by the biological 

 conditions of so peculiar a medium. 



The light does not penetrate to such great depths, but 

 nature, in compensation, endows many abysmal animals 

 with luminous organs. Their tissues are, in certain 

 cases and under certain conditions, phosphorescent, like 

 certain Medusas and various terrestrial animals. Our 

 attention for the present must be turned to the Crustacea. 

 These creatures — the crabs, lobsters, and their allies — are 

 arthropods, breathing by gills. Devoid of an internal 

 skeleton and of a cerebro-spinal system, they are in this 

 twofold respect similar to insects. Filhol, speaking of 

 marine Crustacea — for there are also forms inhabiting 

 fresh water — calls them the insects of the sea, an un- 

 fortunate term, since true insects are not entirely wanting 

 in the sea. Their structure and their embryology have 

 been latterly ascertained, and they have been found to 

 undergo numerous and complex metamorphoses. The 



part in the expedition, captured a new species and 

 gave it the name of Lithodes ferox. It is a very striking 

 animal, of a light-red colour, bristling with spines. It 

 looks like a chestnut which had fallen into the sea, be- 

 come alive, and shot out arms and legs. 



Its powerful and terrible armour has earned it the 

 name ot ferox, for it is impossible to seize it without 

 being wounded, and it must be a very dangerous visitor 

 to its neighbours, so much the more as the Crustacea are 

 very voracious and have the power of reproducing any 

 limbs which have been cut or torn away. 



Rymer Jones, as quoted by Filhol, gives a very curious 

 anecdote. He had one day placed some crabs in an 

 aquarium, when one of them seized one of its companions 

 by the edge of the shell with one of its pincers, broke 

 open the shell with the other pincer, and fell quietly to 

 work to ransack the body, tearing out pieces of flesh and 

 swallowing them ! During this fratricidal feast another 

 crab approached from behind, seized the devourer and 

 holding him firmly, treated him in the same manner. Still 

 he took no notice, but quietly continued his repast until 

 his own death. 



The habits of Lithodes ferox are little known, but, 



