1176 CRUSTACEA. 



concealed by the last thoracic segment or is obsolete. The first or 

 second segment, or both, may bear appendages below, and the latter 

 segment gives exit to the eggs, supporting the external ovarian sac or 

 sacs. 



The Cyclopidae, like the Corycaaidaa, include both subcylindrical 

 and depressed species. 



The species of the genus Cyclops carry two bags of eggs beneath 

 the abdomen, while those of Harpacticus and the allied have but one. 

 Two subfamilies are thus indicated, the Ctclopin^e and HARPACTiciNiE. 

 The former species swim freely in the water, but are incapable of 

 making any progress out of it. The latter, as far as examined by the 

 author, have a much more flexible body, and with a sort of wriggling 

 motion they move themselves readily over a wet surface. They often 

 thus crawl out of the field of view, when upon a piece of glass under 

 the microscope, although the water may be barely sufficient to keep 

 the body wet. A Cyclops in the same condition could not crawl off, 

 but might throw itself to a distance by a spring or leap, by means of 

 the abdomen. 



There appears also to be another group, containing some species 

 with depressed bodies, described by H. D. S. Goodsir.* But the 

 descriptions are too meagre and unsatisfactory for us to determine 

 from them the characteristics of the group. The form is somewhat 

 like that of Sapphirina; but the eyes are minute, and they are in 

 general situated within a short projecting beak or prominence of the 

 front. The superior antennae are short, and in one species, they are 

 represented with two branches, while in the Corycseidse, the superior 

 antennas are always simple or without an accessory branch. The 

 caudal stylets as represented by Goodsir are short subcylindrical, 

 and in one species three-jointed. 



Several new genera have been added to the family Cyclopidaa, by 

 Philippi.f In some cases, we are left by this author in uncertainty, 

 as to whether the genus is characterized by having two bags of eggs 

 or one, and it is therefore doubtful to which subfamily they should 

 be referred. His genera Euryta, Idomene, and Psammathe, we are 

 therefore unable to refer to their true place. From the anterior 

 antennas being appendiculate, Euryta may be related to Harpacticus; 

 yet both this and Psammathe appear to have the habit of Cyclops. 



* Ann. and Mag. N. H., xvi. 1845, 325. 



t Arcliiv f. Naturgeschichte, vi. 186, 1840, and ix. 54, 1843. 



