360 Mr. P. W. Bassett-Smith on 



Hell., C. carangis, Kr., and attached to the trills themselves 

 many specimens of Lernanthropus giganteus, Kr. 



This Caligus appears at first sio-ht to resemble C. infestans 

 of Heller (which I have found also out here attached to the 

 gills of " Cybtum Commersonu"), but is quite distinct, my 

 species being chiefly distinguished by the structure of the 

 first maxilliped, the narrow flat furcula, the presence of only 

 three joints on the fourth perajopod, the large caudal plates, 

 and the surface being spotted with blue instead of red. 



Female. — Carapace slightly broader than long, with ob- 

 tusely rounded posterior angles, narrowing considerably in 

 front, where it unites with the anterior cephalic segment ; 

 this is the frontal plate, rather deeply einarginate in the 

 centre, but thick antero-posteriorly, the lunula? being on the 

 outer third, large and very conspicuous, extending the whole 

 width of the plate. 



Anterior antenna?: first joint equal in length to the 

 width of the lunule, bearing about fourteen delicate plumose 

 papillae ; second joint longer and slender, bearing at its end a 

 number of fine hairs, with an isolated one on its posterior 

 edge. 



Second antennas of moderate size, the terminal claw being 

 rather slender, the spur from the basal joint being distinct. 



Hamulus anterior long, narrow, and curved, springing 

 from a globose base. 



Palp large, sharp-pointed, rising from a bifid base and 

 having a slight curve outwards. 



First maxilliped has the basal joint of the usual shape, the 

 second of a peculiar form, becoming broader at its termina- 

 tion, with the whole inferior border minutely crenate, almost 

 dentate at the end ; this joint terminates in two long curved 

 processes, the outer being the longer and articulate. 



Second maxilliped of comparatively very small size, the 

 terminal claw being short and simple. 



Furcula very distinct, though of only moderate size ; from 

 a dilated base with a narrow neck rise the two branches, 

 which are nearly parallel to one another on the inner border, 

 somewhat rounded on the outer, blunt-ended, and of an ex- 

 tremely flattened appearance, the width of the aperture being 

 less than the length of the arms. 



First per ceopod of the usual form, the palmar joint carrying 

 three short terminal claws, a slender bristle at the angle, 

 and three moderately long plumose hairs from the under 

 border. 



Second perceopod of the usual form. 



Third perceopod of very considerable size, the posterior 



