J204: CRUSTACEA. 



Cephalothorax stout, not depressed, round before and bearing on the 

 front large lenticular corneae (conspicilla), behind usually acute. 

 Abdomen much narrower than thorax, few-jointed, without basal 

 appendages. Posterior antennae monodactyle, larger than the ante- 

 rior feet. Anterior feet, sexually hardly dissimilar, monodactyle, 

 finger slender. Caudal stylets styliform. 



The Corycaei have a stout and short cephalothorax, usually thicker 

 than wide, and commonly acute at each angle behind. The abdomen 

 is three- or four-jointed, and terminates in slender stylets. The pos- 

 terior antennae separate them from the Antariae, the first pair of feet 

 and not depressed body, &c, from the Sapphirinae. 



The cephalothorax is only four-jointed. The anterior segment is 

 large and oblong ; and below at the mouth there is a prominent angle. 

 The front is rounded, and is occupied to a great extent by the large 

 oblate lenticular corneae or consjricilla. There is no appendage to the 

 front, and no beak-like prolongation. The third segment, excepting 

 on a single species of those observed, is prolonged and acute behind on 

 either side. The last segment is smaller and much narrower, and 

 has the angles either obtuse or acutely prolonged, according to the 

 species. 



Besides the division into segments here mentioned, there are indica- 

 tions of other segments sometimes to be observed within the large ante- 

 rior segment. In fig. 5 a, PL 85, six subdivisions may be distinguished, 

 dividing this large segment into seven, the last six very short and 

 nearly equal. If these correspond normally to as many segments, 

 they represent — beginning with the posterior — 1, the first pair of 

 natatories; 2, the anterior feet or maxillipeds; 3, 4, the maxillae, two 

 pairs; 5, the mandibles; 6, the posterior antennae; 7, the anterior 

 antennae. It would seem, however, from the position of the posterior 

 antennae that they should both be considered as belonging to the 

 seventh in this enumeration, and possibly the last transverse pseudo- 

 articulation is incorrectly so considered. 



The lenses of the eyes are situated nearly over the mouth, and 

 more remote from one another than the conspicilla. The latter are 

 sometimes in contact, and as frequently somewhat separate; their 

 diameter is often one-third and occasionally one-half the breadth of 

 the cephalothorax. The vermiform masses of pigment extend back- 

 ward from the prolate lenses, gradually converging and becoming 



