38 



atPcT and ncit defined from the anterioi' lip ; the latter narrow and elongated. 

 Mandililes with tlie masticatory part rather prodnced and without any traee 

 of a molar expansion; palp slender and almost bare except at tlie tij). First 

 pair of maxillae with only a very slight rndiment of a palp, masticatory 1o1)p 

 narrowh- prodnced and divided at the extremity into small nngniform teeth, 

 hasal lobe rather small and narrow. Second pair of maxilhe with both lobes 

 stvlifonn produced. Maxillipeds witli the masticatory lobes veiy large and 

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

 joint rndimentary, knob-like. Anterior gnathopoda rather robust l)ut scarcely 

 suhcheliform, propodos tapering, witliont any distinctly ditined palmar edge. 

 Posterior gjiathopoda slender, with the propodos narrow oblong and densely 

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

 basal and meral joints greatly expanded. Branchial lamcllfp normal. Last 

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

 In-oad. Telson short and bmad, scale-like, more or less incised posteriorly. 

 Rpmarls. — This genus has been established by Pi-nf Lilljeborg 

 chieflv 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 

 tlie latter respect an unmistakalile accordance with the remarkal)lp parasitic 

 form, Trixrhisosfomn, de.scrilied al)ove, though diflFering in most otlier points 

 very deci(ledl\-. Another rather anomalous feature consists in tlie sexual 

 iliffei-ence being here chiefly pronounced in the structure of the superior an- 

 tenna' and not, as usual, in that of the inferior one.s. 



5. Acidostoma obesum, (Sp. Bate). 

 (I'l. i-i, lii;'. -1). 



Anonyx obemift, Sp. Bate, C'at. Ainplii]!. C^rust. Brit, Mus. p. 74, PI. XII, fig. 1. 



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

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

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

 the body; 4th pair deeply emargiuated posteriorly and forming, liclow the 

 emargiuation, an acute angle; 5th pair fully as deep as liroad. Last pair o{ 

 epimeral plates of metasome narrowly rounded posteriorly. First seguient of 

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

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

 antenna^ in female with the 2 outer joints of the peduncle much narrower 

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

 of the [leduiicle, 7-articulate, 1st joint comparatively short and scarcely 



