366 Mr. P. W. Bassett-Smith on 



First perceopod three-jointed ; the first joint has a single 

 hair from the upper border, the second is cylindrical, the third 

 or palmar joint is provided with three short terminal claws, 

 the outer being the longest, and a single bristle at the angle ; 

 I was unable to detect any trace of the usual plumose hairs 

 from the under border. 



Second jierceopod has each branch provided with three 

 joints ; the upper border of each of the outer ones has a single 

 claw ; plumose hairs as in Caligus. 



Third perceopod has the basal flap broad ; on tlie inner 

 surface near tlie centre on each side is a patch of small tooth- 

 like processes about twelve in number, also a single row 

 extending from the hamulus upwards ; the hamulus is of 

 moderate size and strongly curved ; the paddles are small, 

 placed near together, provided with feathered hairs as in 

 Coligus, differing from that described by Kroyer. The last 

 thoracic joint is ill-defined, but it appears of a square form, 

 not projecting below the apron of the third pair of limbs. 



Fourth perceopod well formed, four-jointed, the first joint 

 being cylindrical and muscular, four times as long as broad ; 

 the other three joints are welded together as in Caligus, the 

 terminal giving off three short curved claws placed close 

 together, the outer one being the longest, each of the other 

 joints has a claw of about the same length on its inner border. 



Genitcd segment of a pyriform shape, with a long neck 

 uniting it to the thorax, the whole being three and a half 

 times the length of the cephalothorax, and three times 

 as long as broad ; the intestinal canal and ovaries are 

 easily visible in the dilated portion, the ducts of the latter 

 being placed near together ; from the under posterior border 

 outside these openings is given off on either side a long 

 laminate process more than one third as long as the last 

 segment, protecting the external ovarian tubes. 



Abdomen broad and flat, terminating in two laminate 

 appendages not quite so long as the ventral ones, differing 

 thus markedly from the abdomen of C. lanciniatus. 



The caudal plates are exceedingly small, wedged in 

 between these two processes ; they are slightly longer than 

 broad, and give oft" three fine terminal plumose hairs, with a 

 minute one on the outer border. 



Egg-sacs very long, of a brown colour. 



Length 11-12 millim. 



Alebion, Kroyer. 

 Althion carcharicBj Kr. (PI. XII. fig. 1.) 

 As only a single example of this animal is on record. 



