STALK-EYED CRUSTACEA 203 



short pedicle, with the cornea well developed. The orbits 

 are oval, and have a narrow hiatus at their internal angle, 

 filled by the external antennae. The internal antennae 

 are horizontal and usually entirely hid by the front. 



The epistome is linear, and placed on about a level 

 with the inferior border of the orbits. The fourth joint 

 of the external maxillipedes may be broad, with rounded 

 anterior border, or may be triangular ; the fifth joint 

 articulates with it at its centre, or external anterior 

 angle. The buccal cavity is almost as wide in front as 

 posteriorly. 



The legs of the first pair are stronger, and almost 

 always longer than the others ; they are slightly com- 

 pressed. The last joint of the walking legs may or may 

 not be armed with spines. The male verges arise from 

 the basal joint of the last pair of legs, and are carried 

 through a transverse canal of the sternum. The second 

 joint of the abdomen of the male covers the entire breadth 

 of the sternum below it ; and it extends as far as the basal 

 joint of the last pair of legs. 



Ri\NGE. — Usually in or near fresh water in warm 

 countries. 



Subfamily I. Pseudothelphusinae. 

 Subfamily II. Trichodactylinae. 



Synopsis of the Subfamilies. 



A. Carapace transverse, wider than long. Front with 

 or without superior frontal border, sloping downwards. 

 Fourth joint of external maxillipedes rounded anteriorly ; 

 the fifth joint articulates with it in the centre of its anterior 

 border. Last joint of walking legs armed with spines. — 

 {PseudotJielpJmsiniV?) 



B. Carapace more or less rounded or quadrilateral. 



