EXPLANATION OF PLATES. 



Tab. I. 



rig. 1. Apus cancriformis . 



a. Mandible, b. Mouth. c. Antenna. d. Eirst pair of feet. 

 e. Second do. /. Eleventh do. g. Twelfth do. h. Branchial plate, 



2. Young animal. 3. Do. a little older. 



Tab. II. 

 Fig. 1. Nehalia bipes. 



a. Pirst pair of jaws. h. One of the branchial feet. c. One of the 

 natatory feet. 



3. 3. Arte^nia saliua, male and female. 



Fig. 2, a. Antenna of male. b. Antennule. c. One of the branchial feet. 



4. Do. young. 



Tab. III. 



Figs. 1,2. Chirocephalus diaphanus, male and female. 



Tab. IV. 

 Chirocephalus diaphaiius. 



Fig. A. Antennule. b. Prehensile auteiui;e of male. c. Appendages 

 belonging to them. c*. Profile view of ditto. D. Triangular plate 

 of ditto. E. Head of female in profile, with autennte. f. Dorsal 

 view of dittOj to show the eyes. g. Labrum. H. Mandible. 



In Figs. B, c, c*, E, and F — a, represents the antennules ; b, large 

 antennse ; c, trunk ; d, flexible appendages ; e, triangular plate ; 

 f, organ similar to what is seen in Evadne ; g, eyes ; h, remains 

 of fcetal eye ; i, organ simdar to what Zaddach calls in Apus 

 the glandular processes of stomach ; k, mandible ; vi, labrum. 



Tab. V. 



Chirocephalus diajjhanus. 



Fig. A. Jaws. * One of the setae magnified, b. One of the branchial 

 feet. c. Male organ of generation. 



Fig. 1. Ovum. 



2. Young, half detached from ovum. 



3. Young, while still in internal envelope. 



4. Do. two hours old. 



5. Do. a little further advanced. 



6. Do. in a more advanced stage of development. 



7. Do. still further advanced. 



