88 Mr. F. W. Bassett-Smith on 



Abdomen near its termination broadens considerably, the 

 caudal plates being widely separated. The posterior antennae. 

 are of great size, the terminal hook extending nearly to the 

 edge of the carapace ; but the hamulus anterior is not propor- 

 tionately increased. The other parts are as in the female. 



Length 5-6 millim. 



Lepeophtheirus longipalpus, sp. n. (PI. V. fig. 2.) 



A single well-grown female specimen of this species was 

 obtained from the gills of Arius acutirostris at Trincomalee, 

 with Hermilius longicornis and Caligus arii ; the species 

 is distinctly characterized by the peculiar structure of the 

 maxillary palps and that of the fourth pair of legs. 



Cephalotliorax robust, a long oval; posterior lateral angles 

 obtusely rounded; last thoracic segment well marked, 

 diamond-shaped, with a secondary lobe at the juncture with 

 the genital segment ; the frontal plates are long, with a 

 straight border, having a deep notch in the centre. 



Anterior antenna small, basal joint carrying about seven- 

 teen tine plumose hairs ; second joint of equal length, with a 

 terminal tuft. 



Posterior antennae, : the first joint bears a strong spur 

 directed backwards ; the last joint long, forming a strongly 

 bent claw. 



Mandible of the usual form. Palp rising from below the 

 base of the posterior antennas, and inside the first foot-jaw is 

 in the form of a long blunt curved horn directed inwards and 

 backwards towards its fellow, and reaching almost as far as 

 the furcula ; this condition is quite peculiar, destroying a 

 point which one had looked upon as almost of generic value, 

 viz. the bifid palp. 



Maxillipeds of the usual form. Furcula large, prominent, 

 base broad, with slightly spreading roots ; branches long, 

 almost parallel to one another, blunted at the extremities, 

 the width of the opening being about equal to two thirds the 

 length of the branches. 



First perceopod with a short basal joint, bearing a lobe on 

 the under border; the palm with three minute terminal claws 

 and three long plumose setae from the under border. 



Second perceopod of the usual form, but the upper border 

 of each joint of the outer branch carries a single claw, the 

 outer one being the longest. 



Third perceopod : the two branches are placed close 

 together, each distinctly two-jointed, the terminal joint of the 

 outer carrying six hairs, short, but progressively increasing 



