10 
On the GrneRAL AnAtTomMy, Histotoey, and Puystoiocy of 
Limax maximus (Moquin-Tandon). By Henry Lawson, 
M.D., Professor of Physiology in Queen’s College, 
Birmingham. 
Ir has often occurred to my mind that the objects by 
which we are almost invariably surrounded are not unfre- 
quently those with whose characters and history we are least 
acquainted. How many are there who, though on terms of 
intimacy with the utmost minutiz of some arabesque, or 
specimen of medieval ornamentation, can accurately depict 
from memory alone the pattern of a well-known carpet or 
the design of a drawing-room’s tapestry? If so common- 
place a comparison be not inadequate to the subject, I beg to 
offer it as one of the circumstances which instigated the re- 
searches, upon which the results stated in the following pages 
have been based. 
The variety of L. maximus selected for dissection has been 
in most instances the dark one, with occasional examinations 
of the mottled specimens ; the chief morphological distinc- 
tion between the two, being the possession by the latter of a 
distinct shell, the material of which in the former is usually 
found in a condition of disintegration, mimgled with the 
mucous exudation of the sac in which it is contained. We 
find, according to the philosophic investigations of Prof. 
Huxley,* that the slug, ike other pulmonata, develops in the 
embryonic state, an abdomen or mass of tissue anterior to the 
anal aperture, in this way causing the intestine to bend, with 
its concavity facing the nervous region of the body, and hence 
it comes under the category of molluses, exhibiting a “ neural 
flexure” of the archetype of this naturalist. The arrange- 
ment of the organs included in the economy of gasteropodous 
creatures is generally stated to partake of irregularities, to 
be devoid of co-ordination, and to be asymmetrical. I cannot 
say that I have been forcibly impressed by the truth of these 
dogmas, for to me, a very decided symmetry is apparent, and 
that too, in many instances, of the bilateral type. Thus, in 
the nervous, the circulatory, and the special sense systems, 
* « On the Morphology of the Cephalous Mollusca, as illustrated in the 
Anatomy of certain Heteropoda and Pteropoda collected during the Voyage 
of H.M.S. ‘Rattlesnake’ By T. H. Huxley, F.R.S.”  ‘ Philosophical 
Transactions,’ 1853. 
+ Some difficulty is at first experienced in endeavouring to realise this 
change, but the author’s explanation (vide note, p. 51, of memoir referred 
to) renders the matter most explicit. 
