60 COLLEMBOLA FROM THE SOUTH OEKNEY ISLANDS. 



Fig. 4. Isotoma Brucei, right maxilla (mx.), ventral view, shown in association with the tongue (li>/.), and 

 the right maxillula (mxl.) ; ga., galea ; la.', ventral lamella; la.", inner lamella; sti., stipes; car., cardo ; pa., 

 palp ; pd., foot of tongue ; lig., ligament of tongue. The left maxilla and the left half of the tongue are 

 removed to expose the left maxillula (mxl.'), and its supporting arm, br., x 200. 



Fig. 5. Do. hindmost leg, showing claws, x 200. 



Fig. 6. Do. dorsal view of spring, x 200. 



Fig. 7. Do. dens and mucro of spring, side view, x 250. 



Fig. 8. Do. retinaculum, side view, x 600. 



Fig. 9. Isotoma octo-oculata, var. gracilis, side view, x 40. % 



Fig. 10. Do. left corner of head, showing ocelli, post-antennal organ (p. a. o.), feeler, and antennal 

 organ (a. o.), x 100. 



Fig. 11. Do. hindmost foot, with claws, x 200. 



Fig. 12. Do. tip of dens with mucro, side view, x 300. 



Fig. 13. Cryptopygus crassus, young specimen, x 40. 



Fig. 14. Do. adult female, side view, x 40. 



Fig. 15. Do. ocelli and post-antennal organ of right side of young individual (fig. 13), x 150. 



Fig. 16. Do. ocelli, post-antennal organ (p. a .0.), feeler, and antennal organ (a. o.) of right side. 

 Adult male, x 150. 



Fig. 17. Do. hindmost foot, with claws, x 200. 



Fig. 18. Do. right mandible, ventral view; ap., apical teeth; mo., grinding surface; liu., external 

 shoulder; x 200. 



Fig. 19. Do. right maxilla (mx.), maxillula (mxl.), and tongue (/*.), ventral view; </., galea ; la., 

 lamellae ; pa., palp ; rh. int., internal chitinous rod ; sti., stipes ; car., cardo ; pd., foot of tongue ; lig., liga- 

 ment of tongue. The left maxilla and left half of the tongue have been removed to expose the left maxillula 

 (mxl.), with its supporting arm (br.), and ligament (lig.), x 200. 



Fig. 20. Do. right mandible, viewed from inner aspect ; ap., apical teeth ; mo., grinding surface ; 

 pro., dorsal process, x 200. 



Fig. 21. Do. dens and mucro of spring, adult specimen, side view, x 250. 



Fig. 22. Do. spring, half-grown individual, x 250. 



Fig. 23. Do. spring, very young individual (fig. 13), x 250. 



(BOY. soc. OF EDIN. PROC., VOL. xxvi., PP. 482-483.) 



