350 EXPLANATION OF PLATES. 



TAB. VI. 



Figs. 1, 2, 3. Daphnia pidex ; male and female, and 

 variety. 



TAB. VII. 



Fig. 1. Daphnia Schcefferi, female. 



2. Do. young. 



3. Daphnia pule(c ; variety Icmgispina. 



4. Do. young. 



5. Daphnia reticnlata, female. 



TAB. VIII. 



Daphnia Schcefferi, details. 



Fig. A. Head, principally to show the muscular system, a, u. Basal 

 joint of large antenna, with its elevator and depressor muscles. 

 b. Aiiteunules. c. Eye, with its rotatory muscles, optic nerve, 

 and brain, e, k. Muscles attaching the body of the animal to the 

 carapace, f. Mandible, with its muscles, y. Muscle of the 

 labrum. p. Jaws. 



Fig. B. Head, principally to show the organs of digestion, b, c,f,p, 

 represent the same organs as in fig. A. d. Caecum, e. Stomach. 

 y. Labrum. i. Heart. 



Fig. c. Labrum, with a, b, c, its elevator and depressor muscles. 

 D. Mandible. E. One of the first pair of legs. F. Second do. 

 <;. Third do. H. Fourth do. I. Fifth do. p. Jaws. 



TAB. IX. 



Fig. 1. Moina brachiata. Fig. 4. D. psittacea, young. 



2. Do. young. 5. D.pulex, young. 



3. Daphnia psittacea, 6. D. rotunda, young. 



TAB. X. 

 Fig. 1. Daphnia vetula. 



a. Head magnified to show anteunules. 



2. D. mucronata; var. obtuse rostrata. 



3. D. mucronata; var. acute rostrata. 



4. D. rotunda. 



((. Head magnified to show anlennules. 



