THE YOUNG OF THE CRAYFISHES ASTACUS AND CAMBAKUS 77 



EXPLANATION OF PLATES. 



All figures drawn with camera lucida with Zeiss lenses specified, with few exceptions noted. 

 They are printed one-third the diameter of the drawings, except Figs. 92 and 9.'$, which 

 are nearly life size. 



ASTACUS LENFUSCULUS. 

 PLATE I. 



Figure 1. Larva issuing from egg-shell. 290 mm., aa. 



2. Pantograph enlargement of photograph of living female to show young, several 



hours after hatching, crowded upon the under side of abdomen of mother. 



3. Right side of living larva soon after hatching. 290 mm., aa. 



4. Dorsal view of living larva just hatched, showing split egg-case and long filament 



connecting it to telson of larva. 290 mm., aa. 



5. Front and oblique side views of eyes and rostrum to show its curvature. 2. aa. 

 (i. Dorsal face of left antennule of first stage. 2. A. 



7. Under face of left antenna of first stage. 2. A. 



8. Outer face of left mandible of first stage. 2. A. 



9. Outer face of first maxilla of first stage. 2. A. 



10. Outer face of second maxilla of first stage. 2. A. 



11. Outer face of first maxilliped of first stage. 2. A. 

 12 1 . Outer face of second maxilliped of first stage. 2. A. 



PLATE II. 



Figure 1:1. Outer face of third maxilliped of first stage. 2. A. 



14. Posterior face of left chela of first stage. 2. A. 



15. Posterior face of left second walking leg, first stage. 2. A. 



16. Posterior face of left third walking leg, first stage. 2. A. 



17. Posterior face of left fourth walking leg, first stage. 2. A. 

 IS. Posterior face of left fifth walking leg, first stage. 2. A. 

 19. Anterior face of one of left pleopods of first stage. 2. A. 



PLATE III. 



Figure 20. Dorsal face of telson of first stage, showing internal radiations, marginal spines, 

 and attachment of telson thread. 2. A. 



21. Enlarged views of attachment of telson-thread to certain glandular spines on the 



posterior edge of the telson of first stage. 2. D. 



22. Detail of three such glandular telson spines still covered by cuticle of embryo. 



From a larva just hatched, but not yet shed. 4. D. 



23. Dorsal view of living larva in second stage. 290 mm., aa. 



24. Left side of living larva in second stage. 290 mm., aa. 



25. Upper face of left antenmile of second stage. 2. A. 



26. Under face of left antenna of second stage, with flagellum represented in two 



isolated parts. 2. A. 



1 In this and the sul>sequeiit live figures the anterior arthrobranch has l>een dotted for distinctness. 



