AUTHROPODA. 79 



The Ostracoda are minute freshwater animals, very lively, 

 swimming by the action of their antennae. They do not carry 

 their eggs [about 20 or 30] as in most Crustacea, but deposit 

 them on foreign bodies, fixing them by a greenish filamentous 

 substance. 



Cyprididce. Ilyobates. Cypridinida. 



Bairdia. Loxoconcha, Cypridina. 



Candona. Paradoxostoma. Asterops. 

 Notodromus. 



Cypris. HalocypridcB. Polycopidce. 



Conchoecia. Polycope. 



Cytherida. Halocypris. 



Cythere. Cytherellidce. 



Polycheles. CythereUa. 



Order III. CLADOCEEA. 

 DAPHNIACEA. 



Head distinct ; a bivalve carapace covering the rest of the body . 

 Four to six pairs of feet carrying the branchiae. Second pair of 

 antennae large, branched, acting as swimming-organs. 



The carapace is composed of two valves, joined together on the 

 back. The feet are foliaceous, and are scarcely organs of loco- 

 motion. The eye is single, and very large. 



The Cladocera abound in fresh water, and are very prolific. 

 They are more or less transparent, and have frequent moultings. 

 " Ephippial eggs " are eggs with an additional covering, supposed 

 to be the inner lining of the ovary. They appear to be produced in 

 the winter. 



For Gerstaecker the Cladocera are merely a tribe of a subsection 

 of a section of his suborder " Branchiopoda genuina." (Bronn's 

 Cl. Ord. Thier-Eeichs.) 



PodontidcB. Daphniidce. Acroperus. 



Podon. Daphnia. Pleufoxus. 



Evadne. Moina. Chydorus. 



Bosmina. 



Polyphemid(B. Sididce. 



Polyphemus. Lynceidcs. gida. 



Lynceus. Latona. 



Leptodoridce. Eurycercua. Daphnella. 

 Leptodora. Alona. 



