MORPHOLOGY OF MELIBE 587 



the profuse arboresceiice of the liver. Ao, anal pore ; ^-1^, anterior right 

 papilla; i^, foot ; P, penis ; i?, tentacle, xl. 



Fig. 3. — Photograph of a preserved specimen frcm which the ectoderm 

 and hepatic arborizations of the body-wall have been removed to show the 

 arrangement of the muscles of the body-wall. P, penis, x 1. 



Fig. 4. — Microphotograph of the skin to show the odoriferous glands 

 (Go) ; Hep, hepatic branches ; M, muscle-fibres. 



Fig. 5. — Photograph of a whole-mount of the skin with the underlying 

 fibrous tissue to show the heterogeneous arrangement of the connective 

 tissues. 



Fig. 6. — Photograph of a trans-section of the hood to show the tufted 

 or tuberculate surface of both the external side (Ex) and ventral side (En) 

 of the hood. In the ectoderm of the external side of the hood are also 

 shown the odoriferous (...) glands, which are absent from the ventral 

 side. X 24. 



Fig. 7. — IVIicrophotograph of the body-wall seen from the inside. It 

 shows the caecal endings of the hepatic diverticula. Contrast with 

 fig. 4, which is of the skin, photograph taken from without ; note the 

 relative position of the odoriferous glands in the body- wall. 



Fig. 8. — Photograph of dorsal tentacle with the sense organ (papilla of 

 Gould) (Eh) retracted. C, lamellated part ; K, neural knob. See also 

 K in fig. 15. (Vide Agersborg, 1923, figs. 4, 5, pa.) 



Fig. 9. — Schematic drawing of a dissected adult to show the general 

 arrangement of the visceral organs. A, anus ; Au, efferent branchial 

 veins ; Br, brain ; he, hepatic trunks ; Ft, foot ; G, proventriculus ; 

 Li, larger part of the intestine ; M, mouth ; Mg, mucous gland ; Oe, oeso- 

 phagus ; Od, oviduct ; Ospt, ovispermatotheca ; Ot, ovitestes ; P, penis ; 

 Pc, pericardium ; Prg, prostate gland ; Si, smaller part of the intestine ; 

 Vd, vas deferens ; V, ventricle : Vg, vagina ; Sio, gizzard ; Pd, pyloric 

 diverticulum. 



Fig. 10. — ^Part of the rim of the hood to show the arrangement of the 

 cirrhi. Ic, inner row ; Oc, outer row ; M, muscle-fibres. 



Fig. 11. — Cross-section of a large cirrhus, showing the axis at Lcm 

 from which fibres radiate (Rf) to the sub-epithelial (7e) layer of the peri- 

 phery. Oe, outer epidermal layer, (l.p., cl.) 



Fig. 12. — The axis of the cirrhus shown in fig. 11. Ccni, smaller central 

 ceU-masses with a reticular structure ; Cg, central ganglion ; Lcm, large 

 central cell-mass with a few cells scattered ; Pf, radiating fibres, (h.p. cl.) 



Fig. 13. — Same as fig. 12. Ir, inner reticular network of the large central 

 cell-mass (Lcm) ; Pc, peripheral cells ; Cga, central ganglion. X 1,013-4 ; 

 (o.i., cl.). 



Fig. 14. — Part of the periphery of cirrhus as shown in fig. 13. le, sub- 

 epithelial layer with which the radiating nerve-fibres {Rf) communicate ; 

 Oe, super-epithelial layer, x 1,013-4 ; (o.i., cl.) 



Fig. 15. — Longitudinal section through the sense organ of the dorsal 



