168 Pub. Puget Sound Biol. Sta. Vol. 2, No. 44 



PLATE 22 



a', first antennae. 



a", second antennae. 



a".g, second antennary glands. 



an, anus. 



b, 6rain. 



bu, bulla. 



ch, chitinous exoskeleton. 



g.m, germinal mesoderm. 



i, intestine. 



I, lateral muscles. 



l.l, lower lip. 



m', muscles operating first pair of swimming feet. 



m", muscles operating second pair of swimming feet. 



md, mandibles. 



mxp.g, maxillipedal glands. 



oe, oesophagus. 



s.g, shell gland. 



st, stomach. 



u.l, upper lip. 



za, body wall. > 



Fig. 11. Frontal section of first copepodid larva showing morpho- 

 logical details. X 258.3. 

 Fig. 12. Frontal section through abdomen of first copepodid 



larva showing intestine (i). X750. 

 Fig. 13. Frontal section immediately following that represented 



in Fig. 12^ showing the intestine (i) terminating in a 



distinct anus (an). X750. 

 Fig. 14. Angular section through extreme lower region of third 



abdominal segment of first copepodid larva, showing 



the anal opening (an). XI 125. 

 Fig. 15. Transverse section of first copepodid larva in region of 



mouth tube. X416.7. 



