218 BRITISH ENTOMOSTRACA. 



Avater. For this purpose it curls its body into the form 

 of a ball, and then suddenly returning to the straight 

 position, springs Avith a sudden bound from the bottom 

 to the surface, falling gradually doAvn again to the same 

 place from which it had sprung. 



Hab. Berwick Bay, 1835, not common. 



Family 2 DIAPTOMIM. 



'. Head in general distinguishable from the 

 body, though firmly articulated with the first ring of the 

 thorax. Eoot-jaAvs, three pairs, Avcll developed. Legs, 

 five pairs ; the last pair differing in structure from the 

 others, and differing also from each other in the tAA'o sexes. 

 One eye; sometimes in male sex pedunculated. Right 

 antennae alone, in the male, furnished Avith the SAVollen 

 hinge-joint. 



The habits and manners of the animals of this family 

 are very similar to those of the Cyclopidae. Some are 

 inhabitants of the fresh water, and others arc marine. 

 The manner of hatching their young, and the changes 



O / O 7 O 



these undergo in their progress to maturity, are very 

 similar; only it would appear, from Jurine's observations, 

 that the mother must carry the ova along Avith her, till the 

 young arc hatched, whilst, in the Cyclopida3, the eggs may 

 be hatched, after they are removed from the mother. 



This family contains three British genera. 



1. DIAPTOMIS. Head distinguishable from body. 

 Thorax and abdomen each composed of five segments. 

 Antcnnules two-branched. 



2. TI.MOKA. Head consolidated Avith first ring of 

 thorax. Thorax composed of five, and abdomen of three 

 segments. Antenuulcs two-branched. 



3. ANOMALOCKKA. Head distinguishable from body. 

 Thorax composed of six, abdomen of four segments. 

 Antcnnules not two-branched. 



