24 LAWSON, ON LIMAX MAXIMUS. 
to discover something which might be construed into a duct, 
I have failed signally to detect anything of the kind. This 
gland constitutes a sort of collar surrounding the heart, 
is bordered externally by the lung, and within by the semi- 
circular canal and sector-like sinus; it is of a dark, reddish- 
brown colour, and measures from side to side (including 
heart and sinus), more than + inch. It is made up of a great 
number of lamelle, placed against each other like those 
of a fish gill, and viewed under the microscope, each of them 
is seen to be composed of numerous irregular vacuoles, con- 
taining within them solid, round, non-transparent, incom- 
pressible nuclei. Between the lamellze many blood-vessels 
may be observed travelling from the lung to the heart- 
sinus, and giving off several branches, which, passing between 
the vacuoles, anastomose frequently. The pericardium 
embraces this organ and the heart in its folds, forming on 
the one hand, the floor of the shell-sac, and on the other 
the roof of the thoracic gut-chamber, and, being perfectly 
transparent, admits of our observing most satisfactorily the 
movements of the heart and sinus (fig. 5). I do not appre- 
ciate the necessity for assuming that there is any kidney 
in the economy of Limax; nor, if I did, should I therefore 
conclude, that this gland was its representative simply 
because one of the compounds discoverable in the urine of 
man, was found, or said to have been found, here also; for, 
pursuing the same line of argument, had not the kidney of 
man been discovered, its being known that urea is found in 
the sudoriparous secretion, would constitute a valid reason for 
asserting that the human kidney was located in the skin. From 
the descriptions of some of the earlier anatomists an im- 
mense deal of confusion has resulted, owing to the kidney 
being, according to one or other, termed the muciparous 
gland, organ of the purple, &c., and these being, in turn, con- 
founded with portions of the reproductive apparatus. 
The Nervous System is composed of four separate gan- 
glionic masses, two superior and two inferior, which, by con- 
necting cords, constitute three distinct rmgs. The first ring 
lies upon, the second surrounds, and the third is placed im- 
mediately beneath, the gullet, and springs, as it were, from 
the second. The two latter are by far the most distinct, 
and from the circumstances of their size and contiguity have 
been generally supposed to embrace the entire nervous 
system. The anterior ganglia are two in number, exceed- 
ingly minute, measuring about .'; inch in length, and 
situate on either side of the enlarged oval organ or head, 
