ANATOMY OF THE EARTHWORM. 113 
an undoubted continuity between the cells and nerve-fibres in 
more than one or two instances, although there is good 
reason to believe that such a connection exists. Dr. Rorie, in 
a paper published in this Journal two years since, which can- 
not certainly bear comparison with Mr. Clarke’s,* figures 
multipolar nerve-cells from the ganglia of the earthworm. His 
observations are, in all probability, erroneous, as my own en- 
tirely confirm those of Mr. Clarke, whose accuracy, care, and 
acuteness, are, moreover, too well known to be doubted. 
Functions and Homologies.—'The supra-intestinal por- 
tion of the nervous system evidently presides over the 
operations of the viscera, whilst the sub-intestinal portion is 
more closely connected with the locomotive function. The 
supra-intestinal chain is, however, as we have seen, con- 
nected by its branches with the sub-intestinal ramifications, 
and its roots also are closely associated with those of the 
other nerves arising from the pharyngeal crura. Mr. Clarke 
considers that it combines the office of a sympathetic with 
certain other functions which in many invertebrata are 
entrusted to separate and special centres; such as the labial, 
pharyngeal, and visceral ganglia in cephalophorous mollusca. 
By experiments I have satisfactorily demonstrated to my- 
self that the pharyngeal chain is independent of the other 
nervous centres, although, at the same time, subject to their 
influence, and can control the suctorial movements of the 
mouth and pharynx, and is a centre of reflex action. Mr. 
Clarke has also established this fact by experiment. 
Two parts of the human brain are compared by Mr. Clarke 
to the transverse cephalic band of Lumbricus. One is the 
arched and commissural band of fibres prolonged through the 
corpora quadrigemina, from the upper and inner part of the 
fillet on each side. The other part, which is analogous or 
homologous with the cephalic band, is the corpus callosum. 
Dr. Rorie, in the paper quoted above, advances the opinion— 
stating, at the same time, that he reserves his reasons—that 
the supra-cesophageal ganglia are analogous to the cerebrum 
of man and the higher mammalia, and to the spinal cord, 
whilst the ventral chain he regar ds as belonging to the sym- 
pathetic system, and the pharyngeal crura he considers to be 
the homologue of the vagus. I need hardly say that, as Dr. 
Rorie brings forward no facts to support this view, and as Mr. 
Clarke very ably and carefully gives details of structure and 
anatomy to support his, the opinion of most intelligent per- 
sons will coincide with that of the latter observer. 
Recapirutation.—The hemal system of the earthworm 
* © Quart. Journ. Micro. Science,’ April, 1864. 
