THE POSITION EXPLAINED 409 



have pleopods or rudiments of them. The Phryxiens are 

 considered to represent the stem out of which the other 

 two divisions arise as branches. 



Phri/xus, Rathke, 1843, is preoccupied, but MM. 

 Giard and Bonnier retain it, though transferring Rathke's 

 Phryxus paguri to Athelges. The male has the pleon fused 

 and without appendages. 



Phryxus resupinatus (Miiller), 1870, was found on a 

 Pagarid from Brazil, generally in connection with Pelto- 

 gaster purpv/reus and a Oryptoniscus already mentioned. 

 Pr. Fraisse considers that the name resupiyiatus, meaning 

 with the ventral side outwards, does not really refer to a 

 specific peculiarity, but that the larva places itself under 

 the Peltogaster, naturally with its ventral side towards it, 

 and consequently with its dorsal side towards the Pagurid. 

 When nothing of the Peltogaster is left but its roots, the 

 Bopyrid, having lost its original point of support, bends 

 back its claws to clutch the abdomen of the hermit-crab. 

 That the parasites are not injured by the movement of the 

 Pagurid within the mollusc shell is explained in this way. 

 The hermit by its terminal appendages clings firmly to the 

 twist of the shell, laying its ventral side close to the spindle 

 of it. The parasites, however, uniformly sit on the lelt 

 side of their host's back, tolerably near the carapace, just 

 where the eggs of the healthy female Pagurid are wont to 

 be attached. 



Athelgue, Hesse, 1861, is spoken of as Athelgushj Yritz 

 Miiller in 1870. Athelges is the form generally used. It 

 has a cylindrical pleon and flat laminar branchiae. 



Athelgue paguri (Rathke), 1843, on Eupwjurus bern- 

 hardus (Linn.). In describing this species under the 

 name Phryxus paguri, Bate and Westwood suggest that 

 Athelgue fullode, Hesse, 1861, is a synonym. 



Athelgue Prideauxii, Giard and Bonnier, 1890, on 

 Eupagurus Prideavx (Leach). This species is larger than 

 the preceding, and the adult female retains a rudimentary 

 fifth pair of appendages on the pleon, which are transitory 

 in the former. 



Athelgue guiiarra, Giard and Bonnier, 1890, on Pagurus 



sp. 



30 



