194 



Arthropoda. Class 1. Crustacea. 



live in salt lakes on flat sea coasts, or in inland seas (TJtali) ; some of these 

 forms reproduce parthenogenetically, males appearing only now and 

 again {A. salina in Sonth. Europe). 



rig. 154. Branchipus vernaUs $ . a^ anterior, 05 posterior antenna, / rostrum, 

 stalked-eye, p penis, r caudal appendage, I, II, XI: first, second, eleventh thoracic 

 segments. XH, XIII, the two anterior abdominal segments. — After Packard. 



2. Apus is provided -witli a broad, f eeHy-arclied carapace, wMcli covers 

 the body with the exception of the hindmost part. The lateral eyes are 

 sessile, situated close to one another and near the little nauplius eye on the 



dorsal side of the head. The 

 antennae ai-e very small. There 

 are about sixty pairs of leaf -like 

 legs, whose endopod, as in other 

 PhyUopods, is drawn out into 

 lobes prolonged in the most 

 anterior pair, to form long, 

 jointed threads. In the female, 

 the wide exopod of the eleventh 

 pair is curved like a watch- 

 glass, and the epipod lies upon 

 it as a cover, so that the two 

 together form a little box, in 

 which the eggs are carried about. 

 The caudal appendages are 

 long jointed threads. The shell- 

 glands lie in the carapace, and 

 are visible thi-ough the skin. 

 The individuals of this species 

 are of a. very considerable size 

 (several o/m. long). They are 

 brownish or greenish creatui-es 

 with a thin exoskeleton. They 

 occur, especially in spring, in 

 smaU. fresh- water lakes (often 

 in those which dry up in the' 

 course of the summer), swim- 

 ming with the ventral surface 

 upwards. Usually, and in some 

 species exclusively, females only 

 are found, males occur but 

 seldom. Reproduction is as 

 a rale parthenogenetic. 



3. The genera Estheria, 



Fig. 155. Apus productus, seen from below, 

 o antenna, an anus, I upper lip, md mandible, Pi first 

 leg, r caudal appendage (ends cut off), S carapace. — 

 After H. Milne Edwards. 



