3. Antennae of the female with only one branch; entire animal, including 



the shell, enclosed in a bivalve, transparent case; Family Holopedidae 

 Holopednim Zaddach 

 Not so 4. 



4. Intestine only slightly curved 5. 

 Intestine with one or more coils 18. 



5. Dorsal branch of antennae with two segments; Family Sididae 6. 

 Dorsal branch of antennae with three or four segments 9. 



6. With a beak 7, 

 No beak 8. 



7. Eye dorsal 



Latona Straus 

 Eye ventral 



Pseudosida Herrick 



8. Eye ventral 



Dmphanosoma Fischer 

 Eye dorsal 



Latonopsis Sars 



9. Antennules small in the female, scarcely descending below the tip of the 



head 10. 



Antennules large in the female 14. 



10. Body with a long slender projection from the middle of the posterior 



end 



Daphnia O. F. Miiller (of Family Daphnidae) 

 Body flattened, rounded or slightly pointed on posterior; a spine may 

 project from the junction of the posterior and ventral margins 11. 



11. No beak in the female; usually rounded posteriorly 



Cenodaphnia Dana (of Family Daphnidae) 

 With a beak in the female; usually flattened or slightly pointed pos' 

 teriorly 12. 



12. Dorsal branch of antennae with three segments, ventral branch with two 



segments 



Sida Straus (of Family Sididae) 

 Dorsal branch of antennae with four segments, ventral branch with three 

 segments; Family Daphnidae (part) 13. 



13. Shell noticeably striated; posterior margin flattened and pointed above 



Simocephalus Schoedler 

 Shell scarcely striated; with a spine projecting backwards from the junc 

 tion of the posterior and ventral margins 

 Scapholeheris Schoedler 



14. Antennules projecting from the lower side of the head behind the eye 15. 

 Antennules projecting from the tip of the head before the eye 16. 



15. General shape triangular, with a flattened posterior margin meeting the 



dorsal margin at an angle 



Ilyocryptus Sars (of Family Macrothricidae) 

 Posterior margin rounded or pointed 



Moina Baird (of Family Daphnidae) 



180 



