MOLLUSCA OP PLYMOUTH. 457 



Fig. 2. — Lomanoius. Representation of another, a very lively individual of the same 

 size, en marche. The right rhinophore is retracted into the sheath, the left protruded. 

 The pleuropodial papillas are shown as naturally as possible. The diverticula of the liver 

 are seen through the transparent skin. The heart is on a level with the letters N.S. in the 

 figure. Drawn from life. N.S. = natural size. 



Figs. 3 — 7. — Aplysia punctata, Cuvier. The central tooth and three adjacent lateral 

 teeth of a row about the middle of the radula of five individuals of different sizes, the out- 

 lines being determined by means of a camera lucida. Figs. 4 — 7 are all to scale, as seen 

 with a Zeiss microscope, objective A, eye-piece No. 4. Fig. 3 represents teeth seen under 

 higher magnification with a Zeiss, obj. D, eye-piece No. 2. All the radulse were taken from 

 specimens preserved in spirits ; the buccal masses were boiled in a solution of caustic 

 potash, the radulse being mounted in glycerine jelly. 



Fig. 3. — Animal, ^ inch long x /^ inch broad. Without markings in spirit. 



Fig. 4. — Animal, -^ inch long x -^ inch broad x ^\ high. Without markings. 



Fig. 5. — Animal, 41 x f x f . Markings. — Integuments deeply pigmented with thick, 

 somewhat elongate, black spots, arranged over the whole surface, but here and there 

 leaving clear, unpigmented, round spaces, with indefinitely bounded edges. Small black 

 rings on the head and sides of the neck, but inconspicuous owing to depth and regularity 

 of the other markings. 



Fig. 6. — Animal, 2| x | x 1|^. Markings. — Finely pigmented all over, like the pre- 

 ceding, with a few unpigmented spaces. 



Fig. 7.— Animal, 3 x IJ x If. See text, p. 403. 



Figs. 8 and 9. — Shells, from under side, of Plymouth specimens of A. punctata, natural 

 size. Owing to the method of preservation the calcareous layer cannot be shown. 



Fig. 8. — Animal, li x ^ x |. Markings as in the animal of Fig. 5, but without the 

 small black rings. 



Fig. 9. — Animal, the same as that of Fig. 7. 



Fig. 10. — Shell of an Aplysia depilans, L., from Palermo, in Dr. Norman's collection, 

 natural size, seen from below. The inner line represents the edge of the calcareous layer. 



