Andrews. — Annulus Ventralis. 
PLATE 47. 
Fig. 27. 
Fig. 28. 
Fig. 29. 
Fig. 30. 
Fig. 31. 
Fig. 32. 
Fig. 33. 
Fig. 34. 
Fig. 35. 
Surface view of posterior part of annulus of Cambarus affinis from 
which section shown in figure 14 (pi. 44) was cut; showing sperm 
in the recess and at the sperm angle. 4 X A. 
Ventral view of left-handed annulus of Cambarus affinis fixed in 
Perenyi’s fluid and cleared in oil of clove, before laying. Wax plug 
projects from the orifice, and the tube and recess are full of sperm, 
stained dark. 
Ventral view of isolated annulus of Cambarus virilis showing ante¬ 
rior cushions, central depressed area, and zigzag suture of six suc¬ 
cessive lines. 
Vertical transverse section of end of tube and recess where connect¬ 
ing with surface by a deep cleft, in Cambarus virilis. 2 X A. 
Dorsal view of exoskeleton of same annulus shown in figure 29. 
Posterior view of same annulus. 
Ventral view of posterior part of a left-handed annulus of Cambarus 
virilis , cleared in clove oil. The dotted line indicates the inner end 
of the cleft leading from the suture to the tube; the sperm con¬ 
tents omitted. 2 X A. 
Ventral view of isolated annulus of Cambarus clarkii. 
Anterior view of annulus of Cambarus virilis showing vestibule be¬ 
low; ventral side above. 
