STALK-EYED CRUSTACEA 265 



Synopsis of the Genera. 



A. Transparent cornea very large, occupying at least 

 the half of the length of the ocular peduncles, commencing 

 near their base. — (Ocj'J>oda.) 



B. Transparent cornea very small, ^~\ 



'^ "\~\ 



their extremity. — {Gelasiuiics.) Gciasinms. 



not occupying a quarter of the length of \\ ' ~ / // 

 the ocular peduncles, commencing near 



I. Ocypoda. 



Ocypoda . Fabricius, Milne Edwards, Kingsley, Miers, 



Latreille, Leach, Lamarck, Desmarest. 

 Cancer . Linne. 



Carapace quadrate, moderately transverse and convex, 

 with the dorsal surface closely granulated, the cervical 

 and cardiaco-branchial sutures in part distinct, the antero- 

 lateral angles moderately prominent. The front narrow 

 and deflexed ; the orbits, very large and open, extend 

 along the whole anterior face of the body, between 

 the front and antero-lateral angles, which are not very 

 prominent — their inferior margins are usually divided by 

 a hiatus or fissure. The eye-peduncles, very large, are 

 jointed near the base, the basal part is short, and the 

 terminal portion is often prolonged at its distal extremity 

 as a spine or tubercle ; the corneje, of great size, cover 

 a great part of the inferior surface of the mobile portion 

 of the eye-peduncle. The antennules are partially con- 

 cealed by the front ; the antennas, very small, are placed 

 beneath the eye-peduncles in the narrow hiatus between 

 the base of the antennules and the interior subocular lobe 

 of the orbit, their basal joints are very short ; the flagella 

 scarcely exceed the peduncles in length. The ridges of 



