THE SPIDER CRABS OF AMERICA 



range of the species, but for lack of space no attempt has been made 

 to record all of the many specimens examined in musemn and private 

 collections. 



THE SPIDER CRABS OR OXYRHYNCHA OF AMERICA 



The term Oxyrhyncha owes its origin to Latreille,^ who used it, 

 with a different spelling, in 1803 for one of two divisions of the 

 section "Brachyuri" or short-tailed crabs as opposed to the "Ma- 

 crouri" which included the long-tailed crabs as well as the shrimps. 

 Latreille's "Oxyrinchi" included not only the so-caUed spider-crabs 

 of to-day, but the Oxys tomes and the Euryalidae or Corystidae. 

 In 1834, Milne Edwards restricted the term Oxyrliinques ^ to spider 

 crabs of the families known herein as Majidae and Parthenopidae. 

 Dana in 1852 ^ used the expression "Maioidea or Oxyrhyncha." 

 Miers later * adopts the name Oxwhyncha with the same limits, 

 while Borradaile, 1907,^ adds the family Hymenosomidae to the 

 Oxyrhyncha. It is in the latter sense that the superfamily is used 

 in the following pages. 



By far the greater part of the spider crabs belong to the family 

 Majidae (=Inachidae). The members of this family have usually 

 long, slender legs, which suggest the name " spider crab" ; the chelipeds 

 also are elongate, but are in most cases heavier than the ambu- 

 latory legs. The shape of the body is very diverse, varying from 

 extremely long and narrow with a filiform beak, to broadly oblong 

 or rotund with a short, and either bifid or entire rostrum. All 

 are marine animals and occur in shallow water as well as in con- 

 siderable depths, exceeding 1,600 fathoms, and on aU sorts of bottom, 

 from soft mud to coral rock. 



Spider crabs are notable for their habit of decorating or masking 

 themselves by placing bits of foreign substances on their backs and 

 appendages. The crab picks up, one by one, fragments of seaweed, 

 hydroids, alcyonarians, sponges, or other suitable objects, by means 

 of its claws, using one or the other as needed. He then thrusts each 

 piece into his mouth seemingly to soften the end, then places it on 

 his shell where it is held in place by the hooked hairs which are always 

 present to some extent on these crabs, forming a regular pattern of 

 bands and patches especially on the anterior and lateral portions of 

 the carapace. The artificial covering thus produced serves as a 



' Oxyrinchi (Oxyrinques) Latreille, Hist. Nat. Crust., vol. 6, an XI (1803), p. 85. 



» Oxyrhinques Milne Edwards, Hist. Nat. Crust., vol. 1, 1834, pp. 263 and 266. Cancfiriens Cryptopodes 

 ^formed for the genus Oethra) Milne Edwards, same reference, p. 368. 



> Maioidea Dana, Crust. U. S. E.ipl. Exped., vol. 1, 1852, p. 66. Maioidea, or Oxyrhyncha, Dana, 

 same reference, p. 75. 



* On the Classification of the Maioid Crustacea or Oxyrhyncha, with a Synopsis of the Families, Sub- 

 families, and Genera. Journ. Linn. Soc, Zool., vol. 14, 1879, pp. 634-673, pis. 12 and 13. 



'On the Classification of the Decapod Crustaceans. Ann. Mag. Nat. Hist., ser. 7, vol. 19, 1907, p. 480 . 



