CALIGUS. 45 



of one or two segments ; caudal rami short. Dorsal 

 plates wanting. 



1. Caligus curtus 0. F. Miiller. 

 (Plate XXIV, figs. 1, 2 ; Plate XXV, figs. 7-9.) 



1785. Caligus curtus O. F. Miiller. (86) p. 130, pi. xxi, fig. 1. 



1816. Caligus mulleri Leach. (74) p. 405, pi. xx. 



1832. Caligus bicuspidatus Nordmann. (89) p. 28. 



1850. Caligus diaphanus Baird. (4) p. 269, pi. xxxiii, fig. 1. 



1863. Caligus seglefini Kroyer. (71) p. 89, pi. vii, fig. 3, a-f. 



Female. — Carapace oval and fully half the entire 

 length of the animal, rather longer than broad, widest 

 behind and becoming gradually narrower towards the 

 front, lateral margins slightly rounded, frontal plates 

 tolerably large and furnished with conspicuous lunula?. 

 Genital segment subquadrangular, rather longer than 

 broad, and equal to about one-fourth of the entire length. 

 Abdomen narrow and scarcely equal to one-third the 

 length of the genital segment. Caudal rami very 

 short and furnished with about four short setae. 



Antennules short, the basal joint slightly expanded 

 and its margin densely setiferous ; end joint narrow. 

 The second maxillipeds consisting of a stout basal joint, 

 and an end joint which is narrow and armed with 

 two small terminal claws, one being larger than the 

 other. Branches of the sternal fork short, moderately 

 stout, and slightly divergent, also bluntly rounded 

 at the end. Basal joint in the first pair of thoracic 

 legs tolerably stout, and bearing a single, short, two- 

 jointed branch ; the joints narrow and subequal, 

 the first armed with a short spiniform seta on its 

 outer distal angle ; the last with two short apical 

 spines, and a moderately long one which is curved and 

 claw-like. The fifth pair of legs very small and situated 

 near the postero-lateral angles of the genital segment. 



Length about 10 mm., width equal to about half the 

 Length, bul the size varies to some extent. 



THe species is of a brownish or horn colour, which 

 is apparently uniform, but when viewed with a hand- 



