ANTHURA. 157 
terior of which are soldered together; the fifth is a 
small segment with the hind margin raised and notched 
in the middle, and which supports the latero-caudal 
plates; and the sixth forms the large terminal central 
plate of the tail. 
The family comprises three genera, of which the two 
following are British. 
Genus—ANTHURA. (Leach.) 
The body is very slender, elongated, and somewhat 
triquetrous, having the head and segments of the body 
quite distinct from each other; but the four anterior 

SHAPE OF BODY. 
segments of the tail are confluent, and so closely attached 
together, that, in fresh specimens, or in those preserved 
in spirits, the articulations are not recognizable; the 
penultimate segment of the tail is short, having on each 
side a pair of scale-like appendages, representing the 
terminal pair of tail-legs. 
The pleopoda consist of, at least, four pairs of 
oval plates, strongly ciliated, on each side of the ventral 
surface of the basal segments of the tail. They are 
of nearly equal size, and arranged so as to lie longi- 
