38 



ated and not defined from the anterior lip ; the latter narrow and elongated. 

 Mandibles with the masticatory part rather produced and without any trace 

 of a molar expansion ; palp slender and almost bare except at the tip. First 

 pair of maxillse with only a very slight rudiment of a palp, masticatory lobe 

 narrowly produced and divided at the extremity into small unguiform teeth, 

 basal lobe rather small and narrow. Second pair of maxillse with both lobes 

 styliform produced. Maxillipeds with the masticatory lobes very large and 

 laminar, palp rather slender but scarcely reaching beyond the latter, terminal 

 joint rudimentary, knob-like. Anterior gnathopoda rather robust but scarcely 

 subcheliform, propodos tapering, without any distinctly difined palmar edge. 

 Posterior gnathopoda slender, with the propodos narrow oblong and densely 

 hirsute. The 3 posterior pairs of pereiopoda unusually robust, with both the 

 basal and meral joints greatly expanded. Branchial lamella? normal. Last 

 pair of uropoda extremely small, penultimate pair having the basal part very 

 broad. Telson short and broad, scale-like, more or less incised posteriorly. 

 Remark*. This genus has been established by Prof. Lilljeborg 



chiefly on account of the anomalous structure of the oral parts, which would 

 seem to point to a semi-parasitic life. In fact the present genus shows in 

 the latter respect an unmistakable accordance with the remarkable parasitic 

 form, Trisclusostoma, described above, though differing in most other points 

 very decidedly. Another rather anomalous feature consists in the sexual 

 difference being here chiefly pronounced in the structure of the superior an- 

 tennae and not, as usual, in that of the inferior ones. 



5. Acidostoma obesum, (Sp. Bate), 



(PI. 14, fig. 2). 

 Anonyx olestifs, Sp. Bate, Cat. Amphip. Crust. Brit, Mus. p. 74, PI. XII, fig. 1. 



Body thick and robust, with broadly rounded back. Cephalon com- 

 paratively short, with the lateral corners but slightly projecting and rounded. 

 The 4 anterior pairs of coxal plates very large, more than twice the depth of 

 the body; 4th pair deeply emarginated posteriorly and forming, below the 

 emargination, an acute angle; 5th pair fully as deep as broad. Last pair of 

 epimeral plates of metasome narrowly rounded posteriorly, First segment of 

 urosome slightly impressed at the base dorsally. Eyes rather small, rounded, 

 placed near the lateral corners of the cephalon, pigment light brownish. Superior 

 antennae in female with the 2 outer joints of the peduncle much narrower 

 than the 1st and combined about half its length, flagellum about the length 

 if the peduncle, 7-articulate, 1st joint comparatively short and scarcely 



