OF DENISON UNIVERSITY. 2$ 



Fig. 6. Lower view of anterior part of a larva, about the size of that shown 

 in figure 2, oc. nauplius eye ; Ai, antennae ; ^, eye ; ^, upper ganghon ; ^i, optic 

 lobe ; A 2, swimming antennae (base only shown); M, mouth opening, bordered on 

 either side by commissures passing to the infra-oesophagal ganglion ; Z, labrum ; 

 -M/, mandible and palp ; Mx, first maxilla ; Mx 2, second maxilla ; /, //, ///, IV, 

 etc., feet in different stages of development. 



Plate VI. 



Fig. .1. Chirocephalns larva in an advanced stage, seen from above. 



Fig. 2. Limnetes gouldii, early stage. 



Fig. 3. First right swimming foot of Chiroccphaliis when 1.4 mm. long. 



Figs. 4-6. First, sixth, and ninth feet of younger larva. 



Fig. 7. Abdomen of same. 



Plate VII. 



Fig. I. Larva of Linmetes .3-', mm. long. A, first antennae \ A 2, swimming 

 antennae ; Md, mandiblar palp . e, eye ; /, lense ; Z, liver, budding from anterior 

 part of stomach ; s, sensory filament ; ni, muscles of rectum. 



Fig. 2. Larva of Chij'ocephahis, from below. 



Fig. 3. Caudal stylet of same. 



Fig. 4. Head, showing organs of one side, Z, liver. 



Fig. ^- Muscles of swimming antennae. 



Fig. 6. Maxilla. Fig. 7. End of abdomen of an older individual. Fig. 

 8. Mandible and palpus [p) in this stage. Fig. 9. Antennae of female. Fig. 

 10. Antenna of male ; /; inner ramus ; g, frontal organ. 



Fig. II. Part of Limnetes older than figure I. 



Fig. 12. First abdominal segment of female, seen from below. 



Plate VIIL 



Fig. I. Head of male approaching maturity. 



Fig. 2. Antenna of female, (length of antenna .78 mm.) 



Fig. 3. Antenna of male of about the same age, (length of antenna .79 mm . ) 



Fig. 4. Fourth foot of male ^ inches long. 



Fig. ^. Abdomen of young male. 



Fig. 6. Caudal stylets of same, (.78 mm. long.) 



Fig. 7. Antenna of same. 



Fig. 8. Copulatory organs of one side, m, muscle common to the sheaths of 

 both male organs ; /, penis or forceps ; t, testis. 



./^^. 9. End of sensory antenna ; a, sensory rods, enlarged. 



J^ig, 10, Ykw gf the surface of the basal knob on the male antenna. 



