EEPORT ON THE ANOMURA. 88 



Genus Glaucothoc, II. Milue-Edwards. 



Glaiicotlwc, Jlilne-Edwards, Ann. d. Sci. Nat., ser. le, t. xix. p. 334, 1830 ; Hist. Nat. des Crust., 

 t. ii. p. 306, 1837 ; in Cuvier, Regne Anim., Crust., ed. 3e, pi. xliii. fig. 2, no date. 

 7 Prophylax, Latreille, in Cuvier, R6gne Anim., ^d. 2e, p. 78, 1829. 



Carapace submembranous, with or without a median rostral projection. Ocuhir 

 peduncles well- developed; ophthalmic scales absent. Chelij)edes subequal or unequal, the 

 fingers moving in a vertical plane ; penultimate pair of legs subchelate, the ultimate 

 pair chelate. Abdomen composed of seven distinct segments (including the telson), with 

 submembranous terga, the second to the sixth segments inclusive each provided with a 

 pair of biramous appendages (one of the rami being rudimentary), the last pair forming 

 with the telson a symmetrical swimming fin. 



Although such eminent authorities as Milne-Edwards and Dana placed Glaucothoe in 

 the Thalassinidse among the Macrura, there can now be no doubt, since the discovery of 

 allied forms, that the general characters of this interesting and little-known genus justify 

 its position in the family Paguridse. The form of the abdomen is really its only 

 essentially Macruran character, and this part more than any other is subject to modifica- 

 tion in the Paguridae ; indeed the abdomen is scarcely less developed in Cancellus, a 

 genus the position of which in the Paguridse has never been cjuestioned. It is exceed- 

 ingly probable that we have in Glaucothoe and allied forms, Pagurids of a very primitive 

 tjrpe, still retaining many of the ancestral Thalassinid characters. Mr. Spence Bate, in a 

 paper^ written many years ago, maintains that Glaucothoe is merely an immature stage of 

 Pagurus (or Eupagurus f), and he supports this theory by the description and figures of 

 a larval Crustacean, taken on the surface ofi" the south coast of England ; it seems, 

 however, that these are insufiicient to prove that his specimen belonged to this genus, and 

 he adduces no evidence to show that it subsequently becomes transformed into a soft- 

 tailed Pagurid. The theory that ordinary Pagurids pass through a Glaucothoe-st&gQ 

 prior to taking possession of a shell, and even up to their attaining some size, is rendered 

 improbable by the fact that specimens of Glaucothoe are extremely rare, while Hermits 

 of very small size are frequently met with, in which the abdomen agrees with that of the 

 adult in being soft and imperfectly segmented. The Challenger species described below has 

 all the appearance of an adult animal, and, judging from the nature of its appendages, 

 must have Hved on the bottom. The previously known species of Glo.ucothoe are two in 

 number, viz. Glaucothoe per onii, Milne-Edwards, which probably came from the Asiatic 

 seas, and Glaucothoe rostrata, Miers, taken by the " Alert" off Madeira, at a depth of 15 to 

 50 fathoms. The genus Prophylax, Latreille, of which the type specimen has apparently 

 been lost, is very closely allied to and perhaps identical with Glaucothoe ; the latter name 



' Ann. and Mag. Nat. Hist., ser. 4, vol. ii. p. 116, pi. ix., 1868. 



