PLATE 1. 



{Drawn and engraved by C. F. Gissler.) 



EXPLANATION OF FIGURES. 



Fig. 1. Nervous system of Amblychila. Natural size. 



rt, antennal nerve [natural position is behind the optic nerve] ; b, eye ; c, 

 supraoesophageal ganglion; d, infraoesophageal ganglion; e, first thoracic gan- 

 glion; y, second thoi'acic ganglion; g to k, first to fourth abdominal ganglia; I, ter- 

 minal cords; m, fifth abdominal ganglion; n, ventral pair of nerve cords arising 

 from the infraoesophageal ganglion. 

 Fig. 2. Optic nerve with swelling and ganglionary expansion. Enlarged. 

 Fig. 3. Vertical section through cornea and crystalline lenses; the latter are convex, 



interior prolongations of the cornea. Enlarged. 

 Fig. 4. Alimentary canal. ^ Slightly enlarged. 



aa, pharynx; a, oesophagus ; b, ingluvies; c, proventricular triturating muscular, 

 apparatus; d, Malpighian vessels (shortened); e, accessory glands (shortened); 

 J] chj-lific ventricle; g, rectal bladder; h, rectal cells. 

 Fig. 5. A rectal cell, moderately magnified. 

 Fig. 6. Wall of a rectal cell, highly magnified. 

 Fig. 7. Elytral pores. 



«, small and plain pore of the elytron: b, large ring-pore of the elytron; c, large 

 ring-pore interrapted by a concave groove. 

 Fig. 8. Anterior external coat of chylific ventricle. 



a, fibrous network moderately magnified; b, one of the meshes highly magnified. 

 Fig. 9. Male sexual organs. Slightly enlarged. 



a, testicle; b, vas deferens (the swollen part = vesica seminalis); bb, Ductus 

 ejaculatorius ; c, process of preputium; cc, base of penis; cp, preputium; d, 

 penis; e, distending process; ee, corneous ridge of preputium. 

 Fig. 10. Chorion of egg. Magnified. 

 Fig. 11. Micropyle of chorion. Highly magnified. 

 Fig. 12. Chitinous process in head. Enlarged. 



rt, bifurcate insertion; b, process; c, membrane. 

 Fig. 13. Penis. Slightly enlarged. 

 A, of Amblychila; B, of Omus. 

 Fig. 1-1. Portion of pharynx. Moderatel}' enl-arged. 



a, tracheal branch ; b, longitudinal glandular fold; c, polygonal glandular cells; 

 (/, ring-muscles; e, longitudinal muscle-fibres; y, transverse glandular fold. 



