92 E. A. ANDREWS. 



Explanation of Figures. 



Fig. I. Cambarus virilis : I, posterior face of left stylet of adult, ^ctq ; 2, median 

 face of the same, ^a^ ; 3, cross-section of the stylet at the level, jp/, Fig. 2, 2A. 

 Cambarus Diogenes : 4, median face of left stylet, 2a^ ; 5, section across the above 

 at the level, 5) 2 A ; 6, posterior face of the left stylet, 20^. Cajtibartts Clarkii : "j, 

 median face of left stylet, 20^ ; 8, enlarged view of external face of tip of left stylet, 

 2, 90 mm., A ; 9, section across stylet at level, 9, of Fig. 7, 2A. Cambarus monte- 

 zumcE : 10, bases of second and third left legs, showing hooks, of male 30 mm. long, 

 anterior view, 20^; 11, median face of left stylet, 2, 90 mm., A ; 12, cross-section 

 on the level 12 of Fig. 11, ^A ; 13, cross-section of same on level 13, ^A. 



Fig. 2. Astacus leniusculus : 14, posterior face of left stylet turned to show 

 somewhat of the median face, 20^; 15, section across the above at the level 15 of 

 Fig. 14, 2D; 16, cross-section at the level 16 of Fig. 14, 2, 90 mm., A ; 17, cross- 

 section at the level 17 of Fig. 14, 2, 90 mm., A ; 18, cross-section at the level 18 

 of Fig. 14, 2, 90 mm., A ; 19, papillse, or stylet on the first abdominal somite of lar- 

 val shell passing from the fourth to the fifth stage. Length of body, 19.5 mm., 2, 

 aa ; 20, stylets of a male 20 mm. long, 2, 90 mm., A ; 21, left stylet of a male 23 

 mm. long, 2 A ; 22, stylet of a male like the last, 2 A ; 23, left stylet of a male 25 

 mm. long, posterior face, 2A ; 24, second, or accessory, stylet; anterior face, some- 

 what turned to show the external face in part, ^^q ; small figure to the right is the 

 enlarged end of the radius ; 25, part of the edge of the endopodite of the accessory 

 stylet of a male 23 mm. long, anterior face, 2D ; 26, posterior face of the same, 2D ; 

 27, anterior face of the endopodite of the accessory stylet of a male 25 mm. long, 

 2A ; 28, cell outlines over elevation and pit of the edge of the endopodite of above 

 stylet, 2D. 



