LAWSON, ON LIMAX MAXIMUS. ry 
we find the constituent organs equally divided between the 
two sides of the body, and there are two salivary glands and 
two principal divisions of the liver, one of each lying on either 
side of the median line. The lungs we may also, to some 
extent, distribute with reference to a central plane; and, finally, 
there remain but the generative and digestive apparatuses, 
which, though seemingly aberrant, we are not warranted in 
concluding to be asymmetrical till better acquainted with their 
phases of development. In a rude way we may look on this 
animal as a tough, elongated pouch, contaiming viscera, and 
having attached to its dorsal surface, on its anterior third, a 
convex and in some measure pyramidal cap, which is com- 
posed of the so-called mantle; this, in vertical section, is 
dome-shaped, and is a perfectly closed cavity, in which is 
placed the loose mass of calcareous particles of the shell ; 
below, it is limited by a delicate, transparent membrane, which 
lies upon the heart and pericardial gland, and appears by a 
process of splitting to pass beneath these latter also, in this 
manner completely separating them from the great visceral 
chamber subjacent (see Pl. II). I propose to treat of the 
anatomy of Limax after the following scheme : 
1. Tegumentary system. 5. Circulatory system. 
2. Muscular system. 6. Nervous system. 
3. Digestive system. 7. Special sense and glandsystem. 
4. Respiratory system. 8. Reproductive system. 
Integument.—The skin system is of the musculo-cutaneous 
type, and may be said to consist of three coats, an outer or 
dermoid, a middle or muscular, and an internal or fibro-vas- 
cular, and calcareous. The first resolves itself into two layers, 
a more external stratum, which is transparent, and, so far as I 
could observe, structureless, and in some instances detachable, 
and within this a bed of fusiform endoplasts, imbedded in a clear 
matrix, and which assume the fibrous appearance of connec- 
tive tissue as they approach the next coat, from which they 
are inseparable. The muscular or central lamina is also com- 
posed of two layers of fibres, the most external being longi- 
tudinal, and those within them transverse, yet the line of 
distinction cannot be clearly drawn, for as you advance 
inwards you find the outer fibres gradually losing the longi- 
tudinal and by assuming an oblique position, in this way 
passing almost insensibly into the truly transverse ones; the 
fibres, at best, are indistinct, and are composed of elongate 
endoplasts. The imner coat consists of meshes of connec- 
tive tissue, tunneled for the conveyance of the venous blood, 
and impregnated with round, granular particles of carbonate 
