Fig. 
Fig. 
EXPLANATION OF PLATES. 
The central nervous system of Helix Pomatia L.; after Branpt 
and Ratrzesure Mediz. Zool. u. Tab. 34, fig. 12; compare p. 766 ; 
1, ganglion situated above the esophagus; 2, below it. 
Blood-circulation of Helix Pomatia L.; after Cuvier, as an 
example of the Pneumonica, p. 811; a, heart; c, auricle, both 
lie in the pericardial sac, laid open; 0, 0’, arteries; e, e, venous 
currents, from which the pulmonary veins in the respiratory 
cavity arise, which pass into the trunk d that runs to the 
auricle ; f, f, calcareous sac or kidney which surrounds the peri- 
cardium. Compare pp. 760, 761. 
Limax ater L., the anterior portion of the animal, after BRANDT 
u. Ratzes. op. cit. Tab. 38, fig. 3, (Arion empiricorum brunneus). 
A, respiratory aperture at the margin of the mantle. See 
p. 817. 
Circulation of the blood in a cephalopod molluse, Loligo, after 
Cuviger Tabl. élém. de [ Hist. nat. des Animaux; a, vena cava, 
which divides into two branches; 6, 6, lateral or venous hearts ; 
c, c, branchial veins; d, d, space where the gills are situat +d ; f, 
the middle or arterial heart ; g,g,g, arteries. The direction of 
the current is indicated by arrows. Compare pp. 762 and 819. 
A. small specimen of Sepia officinalis L., p. 829; after Carus 
Nov. Act. Acad. Ces. Natur. Curios. Xi1.; a,a,@,a,a,a,a,a, the 
eight conical arms, the two long thin arms are seen at 0, b; ¢, 
funnel; comp. pp. 818, 819. 
Detached arm (ectocotylus) of a male individual of Argonauta 
argo serving for copulation (magnified about three diameters) ; 
after KoELLIKER (Berichte der Zoot. Anstalt zu Wiirzburg, 1849, 
Tab. 1. fig. 19); comp. pp. 821—823. 
