Andrews. — Annulus Ventralis. 
Fig. 36. 
Fig. 37. 
Fig. 38. 
Fig. 39. 
Fig. 40. 
Fig. 41. 
Fig. 42. 
Fig. 43. 
Fig. 44. 
Fig. 45. 
Fig. 46. 
Fig. 47. 
Fig. 48. 
PLATE 48. 
Fig. 36-40, Cambarus clarkii. 
Dorsal view of exoskeleton of same specimen as shown in figure 34 
(pi. 47); anterior is above in figure. 
Posterior view of annulus showing sloping sides and steep posterior 
face. 
Anterior view of annulus showing deep valley leading up to slit in 
anterior edge of central elevation. 
View from left, of thick longitudinal vertical slice of annulus, cleared 
in clove oil. The bottom of the tube is indicated by the heavy 
line; the posterior is to the left. 2 X A. 
Ventral view of annulus from which the exoskeleton has been re¬ 
moved, showing the epidermal groove in which lay the exoskeletal 
trumpet. 
Fig. 41-44, Cambarus bartoni. 
Ventral view of isolated annulus of a female 73 mm. long. 
Dorsal view of exoskeleton of same annulus. 
Anterior view of same annulus. 
Posterior view of same annulus. In the foreground the posterior 
face, in the background the long anterior face; between is the 
transverse part of the trumpet. 
Fig. 45-48, Cambarus immunis. 
Ventral view of isolated annulus. 
Dorsal view of exoskeleton of same annulus. 
Posterior view of annulus. 
Ventral view of posterior part of annulus cleared in clove oil, but not 
decalcified. 2 X A. 
