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Duthiers himself, have stated that the sac derives its nerve 
in the large majority of cases (the Heteropoda and Eolidae 
being exceptions), from the pedal ganglion, and the supposed 
innervation of the organ from the pedal ganglion led to 
various deductions as to the inconstancy of the innervation 
of homologous parts, and the connection between sensory and 
motor nerve-centres. M. Lacaze Duthiers has recently care- 
fully looked into this question, and believes that he and other 
observers have been misled by the apposition of the otolithic 
sacs to the pedal ganglion, and that the auditory nerve comes 
to the sac really from the supra-oesophageal, also called cere- 
broid ganglion, and thus this ganglion is the nerve-centre of 
all the sensory organs. Dr. Lacaze Duthiers is an observer 
of the very greatest distinction and of known accuracy; we 
therefore must expect to see his observations confirmed, and 
would point to this inquiry as a worthy task for any of our 
readers. It is much to be regretted that these observations, 
so important in connection with the homologies of the Mol- 
lusca (for it was usual to determine the homologue of the 
pedal ganglion by the connection of the otolithic sac in 
doubtful cases) , have been totally misrepresented in the pages 
of the ' Monthly Microscopical Journal/ and in the ' Popular 
Science Review/ The error has arisen from imperfect 
knowledge of the French language, and of the rudiments 
of molluscan anatomy. 
Throughout the translation of Dr. Duthier’s paper in the 
February number of the 'Monthly Journal/ the term " sus- 
cesophagien” is translated " sub-oesophageal/’ instead of 
" supra-oesophageal,” and thus the very fact which Dr. 
Duthiers denies is most emphatically asserted in the transla- 
tion of the paper ; and the same mistake is made in the 
Chronicle of the 'Popular Science Review’ for January. Is 
it possible that Dr. Lawson’s contributor knows that in Mol- 
luscs the cerebral ganglion is supra-oesophageal, and the 
pedal ganglion is sub-oesophageal? The following passage 
and the subjoined translation in the ' Monthly’ would lead 
one to suppose that it is impossible: — "Toujours le nerf 
acoustique prend son origine sur les ganglion sus-oesophogie 
ou cerebral.” "The acoustic nerve invariably takes its 
origin from the suboesophageal or cerebral ganglion.” 
‘Monthly Mic. Journal/ February, p. 115, six lines from 
top fand again two lines from the bottom). 
We regret much that the space of a useful contemporary 
should have been wasted in propagating such error as the 
above. It is most necessary for us to correct it, as the obser- 
vations of Professor Lacaze Duthiers on the subject are of so 
