582 



ones being much the larger, and, in the male, very powerfully developed, with 

 the propodos much expanded. The 2 anterior pairs of pereiopoda with the 

 basal joint comparatively broad and laminar; the 3 posterior pairs strongly 

 built, with the propodal joint much expanded distally, so as to form together 

 with the dactylus a kind of subcheliform hand. Last pair of uropoda with 

 both rami lamellar, the outer one exhibiting 2 strong recurved hooks, the 

 inner one setiferous at the tip and without any spines. Telson terminating with 

 2 juxtaposed, strong, recurved hooks. 



Remarks This genus was proposed in the year 1857 by Sp. Bate, 

 to include a form detected by him, and differing from Amplutho< : in the 

 inverted longitudinal relation of the 2 pairs of antennae. Subsequently he 

 withdraws the genus, and placed the species within the genus Amphithoe. 

 He was, however, not aware, that he, at the same time, referred the female 

 of the same species to a new genus, Sunamphithoe. I think there is some 

 reason for retaining the genus originally proposed by Sp. Bate, since the form 

 upon which it was founded in fact differs from Amphithoe. not only in the 

 structure of the antennae, but also in several other characteristics apparently 

 of generic value, for instance, in the peculiar subcheliform character of the 3 

 posterior pairs of pereiopoda, and in the strongly-hooked telson. Moreover, 

 there are to be found some differences in the structure of the oral parts. The 

 genus comprises as yet but a single species, to lie described below. 



Pleonexes gammaroides, Sp. Bate. 



(PI. 201.) 

 Pleonexes gammaroides, Sp. Bate. Ann. Nat. Hist. 1857. 



Syn : Sunamphithoe hamulus, Sp. Bate J . 

 Amphithoe gammaroides, Sp. Bate 5 . 

 Sunamphithoe longicornis, Boeck. g 

 Sunamphithoe gammaroides, Stebbing. 



Body comparatively strongly built, though somewhat elongated, with 

 the back broadly rounded. Cephalon with the frontal part but very little 

 produced, lateral corners evenly rounded, postantennal ones strongly produced 

 below, the edge between the two being nearly straight. Anterior pairs of 

 coxal plates but very little deeper than the corresponding segments; 1st pair 

 obliquely expanded distally; 5th pair with the anterior lobe fully as deep as 

 tin- preceding pair, and evenly rounded at the tip. Last pair of epimeral 

 plates of metasome obtusely rounded at the lateral corners. Eyes small, 



