272 BRITISH ENTOMOSTRACA. 



Abdomen very short and rounded, broader than long. 

 Caudal plates terminated by three tolerably long, plu- 

 mose setae. Sternal fork with simple, short, obtuse 

 branches. Second pair of foot-jaws very long ; the last 

 joint being narrow, long, and terminated by two curved 

 claws, one longer than the other. Fourth pair of legs 

 stout ; the first joint broad and thick, the last ending in 

 one long, stout, curved claw, which is serrated on its 

 inner edge, and two short ones. Oviferous tubes of 

 considerable length. 



Male. In the male the last joint of thorax is consider- 

 ably smaller than in the female, and more rounded ; the 

 lobes much sharper, and terminated by the same tubercles, 

 but of a larger size. Abdomen about two thirds the 

 size of the last joint of thorax. Second pair of foot-jaws 

 large. 



Hah. — Belfast Bay, W. Thompson, Esq. Taken from 

 the cod and brill, February, March, November, and De- 

 cember; MerJangus poUacldus, March 1840; the brett 

 {Rhomhis vulgaris), March, November, December, 1837 ; 

 Merlangus vulgaris, Flem., March, December, 1837; 

 Corregonus 2Jollan, Lough Neagh, November and Decem- 

 ber 1837 ; Gadus cEgelfiiius, December 1837 ; the plaice, 

 Belfast, February 1844 ; Mugil chelo, Belfast, April 

 1840. 



4. Caligus centrodonti. Tab. XXXII, figs. 6, 7. 



Female. Carapace obovate ; very much narrower in 

 front than posteriorly. Frontal plates well developed, 

 deeply notched in the centre. Lunules large, and nearly 

 round. Basal joint of antenna3 large. 



Thorax much smaller than carapace ; last joint quadran- 

 gular-shaped, narrow superiorly where it articulates with 

 peiuiltimate joint, and crescentic at inferior edge ; nearly 

 as broad as long ; at each angle inferiorly giving off a 

 small tubercle, armed with two seta?. 



