35 



Gen. 9. BryaxiS, Boeck M. 8. 



Generic Characters. Body short and robust, with the anterior division 

 considerably tumefied. Cephalosome wholly confluent with the 1st pedigerous 

 segment, and having the lower edges deeply insinuate at the oral region, front 

 without any trace of a rostrum below. Lateral corners of last segment of m eta- 

 some produced to acute lappets. Urosome nearly as in Undinopsis. Eye wholly 

 absent. Anterior antennae comparatively short and robust, 24-articulate, and densely 

 clothed with ciliated bristles. Posterior antennae with the outer ramus poorly 

 developed. Mandibles with the palp exceedingly large, rami very unequal. Maxillae 

 and anterior maxillipeds about as in Undinopsis. Posterior maxillipeds very 

 largely developed, with a peculiar sensory appendage at the end of the 1st basal 

 joint. Legs of a structure similar to that in Undinopsis. Male unknown. 



Remarks. This genus, to which the M. S. name Bryaxis had been applied 

 by Boeck, is allied to Undinopsis, although it differs rather markedly in the absolute 

 absence of both rostrum and eye, as also in the structure of the posterior antennae, 

 mandibles and posterior maxillipeds. It contains as yet only a single species, to 

 be described below. 



14. Bryaxis brevicornis, Boeck, M. S. 



(PL XXII, XXIII). 



Specific Characters. Female. Anterior division of body, seen dorsally, 

 regularly elliptical in outline, greatest width nearly attaining half the length, 

 anterior extremity evenly rounded, posterior somewhat contracted; seen laterally, 

 evenly vaulted anteriorly, front obtuse, without any trace either of a rostrum or 

 tentacular appendages below, inferior edges of cephalosome remarkably inflexed 

 in the middle. Lateral lappets of last segment of metasome very acute and 

 obliquely upturned. Urosome scarcely attaining y 3 of the length of the anterior 

 division. Caudal rami short, rounded at the tip, apical setae rather elongated. 

 Anterior antennae much shorter than the anterior division of the body, all the 

 articulations sharply defined and clothed with very strong, ciliated bristles. Posterior 

 antennae with the outer ramus not even attaining half the length of the inner, and 

 6-articulate, last joint very small, with the apical setae rudimentary. Inner ramus 

 of mandibular palp poorly developed, with only 4 apical setae. Sensory appendage 

 of posterior maxillipeds club-shaped. Colour bright yellow. Length of adult 

 female 2.60 mm. 



