510 MR. W. E. COLLINGE ON A NEW GENUS AND 



cup-shaped organs (fig. 2). Appendages marked with lattice-work-like orna- 

 mentation (fig. 9). Cephalon (figs. 3 & 4) convex above and with numerous 

 cup-shaped organs, median and lateral lobes conspicuous ; epistoma raised in 

 the median line with two lateral concavities. Eyes prominent, situated dorso- 

 laterally almost above the cup-shaped lateral lobes o£ the cephalon. Anten- 

 nulse 3-jointed. Antennae (fig. 5) of medium length, the 5th joint being the 

 longest ; flagellum 3-jointed, with subequal divisions and terminal style. 

 1st maxillae (fig. 6), outer lobe terminating in four large curved spines and 

 four small ones with bifid terminations. The segments of the mesosome are 

 somewhat flattened, the lateral plates of the 1st partly surround the cephalon, 

 all have their posterior angles slightly produced and overlaj) one tinother, 

 fringed with numerous cup-shaped organs. Maxillipedes (fig. 7) with the 

 outer palp terminating in a large multispinous process and t\\ o smaller inner 

 spines with broad bases ; the inner palp has two marginal tooth-like spines. 

 Thoracic appendages (fig. 8) comparatively short, ornamentation strongly 

 marked, densely covered with setse and spines, and terminating in strong 

 claw. Uropoda (figs. 10 & 11) somewhat globose, basal plate with anteriorly 

 raised margin, external antero-lateral margin produced inwards slightly ; 

 exopodite short and thick, outer border almost straight ; endo{)odite same 

 length as exopodite, articulating beneath the anterior raised margin of the 

 basal plate, both setaceous and with terminal hair-like setoe. Telson (fig. 12) 

 triangular with posterior margin bluntly rounded. Length 2'8 mm. Colour 

 (in alcohol) horny-brown with darker lateral portions or with dark median 

 line. 



.Habitat. Beneath the bark of trees, Botanic Gardens, Georgetown, 

 Demerara, British Guiana. 



Type. In collection of W. E. C. 



This species is of special interest, in that it possesses a very peculiar series 

 of chitinous organs on the body-segments and cephalon. In the spirit-' 

 preserved examples they do not exhibit any structure beyond that shown in 

 figure 2, viz., a cup-shaped organ with a tube-like body in the centre. 

 Dollfus (4) has figured some similar bodies on the telson of Platyarth-us 

 (?) simoni, Dollfus, from Venezuela, and Budde-Lund (8) describes and 

 figures very similar ones on the telson and metasome of another Venezuelan 

 species, Trichorhina quisquiliarum (B.-L.). His brief description is as 

 follows : — " margo posterior omnium segmeutorum serie papillarum 

 minutissimarum ornatus.^^ 



The form of the cephalon is unlike that in any other genus I am ac- 

 quainted with, the eyes being being very prominent and situated almost 

 above the cup-shaped lateral lobes, whilst the median lobe is prolonged 

 forwards and slightly downwards. The two lateral concavities on the 

 epistoma are also characteristic. 



