SIMKOTH : ON NEOnYALIMAK. 41 



relate to tlie roof only. This presents a honeycombed structure, 



111 irked over with bhick, wldch disappears towards the left side. 



The pigmentation is most intense at the periphery. Thence some 



l)lackish thr(!ads radiate towards the pericardium : this bhickish net- 



^\•ol■k attains its greatest density in the right corner of the pulmonary 



I ii\ity, where respiration is most active. Tliese blackish rays are 



\isible frum the outside through the shell and the mantle wall. 



I'lie position of the heart is remarkable, it being situate on the 



short base of the elongate, triangular, yellow kidney, or ncphridium. 



The latter bears the secretory lamellae on its upper side, and these 



lainelhc are bound togothtu- by transverse, oblique connectives. 



I The pigment. — In addition to its occurrence in the roof of the 



pulmonary chamber, melanino is deposited in certain places in the 



interior of the animal, viz. — (1) As in all Stylommatopliora, in 



the great, brown retractor muscles of the ommatophores ; (2) in the 



j wall of tlie hermaphrodite duct (PL V, Fig. 9, h.d.) ; (3) on the surface 



i of the hermaphrodite gland, or gonad. This gland is situated on the 



, left side, behind the liver, and is partly covered by a thin projecting 



j portion thereof ; it bears, on its outer side only, an ink-like spot of 



; pigment, which also extends partly over the projecting process of tlie 



liver. 1 think the only conclusion to be drawn from this distribution. 



I of the pigment is, that its deposition results on the one hand from 



I activity of growth, or function, and on the other from the action of 



light. Probably its deposition in the body-wall corresponds with the 



, distribution of tlie nerves. 



I The alimentary system.. — The pharynx and the alimentary canal, 

 ( with the salivary glands and the two digestive glands, have the general 

 I form shown on PI. V, Fig. 6. The jaw (Fig. 7) is brown, and has 

 a sharp edge, with a slight median process {oxyynath) and a lighter- 

 coloured palatal plate [elasmoynat])), the two posterior coi'ners of 

 which are somewliat prominent. This plate is finely sculptured, the 

 thread-like markings converging towards the itiedian projection. lu 

 tiie radula (PI. V, Fig. 8) the median tooth is tricuspid, the middle cusp 

 ] being very large. In the lateral teeth the median cusp is still larger, 

 and directed oblitpiely towards the middle line of the radula ; the inner 

 cusp is reduced in size, whilst tlic outer one is duplicated. In the 

 marginal teeth the inner cusp increases in size, whilst the exterior 

 I outer cusp subdivides, giving rise to three outer cusps (PI. V, Fig. 8, 

 [ No. 20). It is, however, uncertain whether the outermost tooth in 

 I the figure be a true marginal. The contents of the stomach were 

 somewhat darker than is usual in carnivorous slugs. Plant fibres were 

 observable. I came to the conclusion that the animal had not fed on 

 green leaves, but on dead ones, that had fallen to the ground, on 

 which it lives. 



Genitalia. — The specimen is fully developed. The tubules of the 

 roundish gonad converge towards the black hermaphrodite duct, which 

 terminates in a small, slender, pale vesicula seminalis (PI. V, Fig. 9). 

 The albumen gland is yellow, small and kidney- shaped. Immediately 

 beyond this the male and female ducts separate, no true hermaphrodite 

 duct being formed. The male duct, or prostate, is wide and glandular, 

 ( 



