The learned Author of the Hore Entomologice, in that 
part of his valuable essay relating to the Molluscz, considers 
our knowledge of these animals too imperfect to enable him 
to state the nature of the typical groups: the situations of 
which, in his diagram of the animal kingdom, are therefore 
merely indicated by stars. M. Macleay further remarks, 
that the Gasteropoda of M. Cuvier, with certain restrictions, 
evidently form a circular group. Yet, from the above 
omission, it appears he still entertained some doubts on the 
propriety of this arrangement. Labouring under similar 
disadvantages to those which impeded the researches of so 
profound an observer, we feel some hesitation in expressing 
a different sentiment on the subject, particularly in reference 
to his own disposition of affinities. 
It is evident that these typical groups, whatever may be 
their nature, must present some very strong points of ana- 
logy to those in the circle of Vertebrata: and that such 
analogies should extend to the corresponding groups of the 
Annulosa. This we should expect, not only as the necessary 
result of a truly natural arrangement, but as a primary test, 
by which the correctness of any series of affinities must be 
tried. Now admitting that Quadrupeds and Birds shew 
the same typical perfection among the Vertebrata, as the 
Mandibulate and Suctorial Insects unquestionably do in 
the Annulosa, we have two beautiful analogies between 
these otherwise dissimilar groups, taken from one of the most 
important functions of nature. Quadrupeds and mandi- 
bulate insects are provided with jaws for tearing and mas- 
ticating their prey, while in birds and suctorial insects, the 
mouth is lengthened into a proboscis, by which nourishment 
is imbibed by suction. These analogies are equally con- 
spicuous among the Mollusce. The Phytiphages of Lamarck 
(of which the garden snail is a good example), are furnished 
with jaws and masticate their food: the Zoophages of the 
same accurate observer, have their mouth elongated into a 
retractile trunk or proboscis, by which they pierce through 
other shells, and suck the juices of the inhabitant. To 
insist on the importance of these distinctions, employed as 
they have been to characterize primary divisions, is surely 
unnecessary. That they will be subject to considerable 
modification, in the subordinate groups, may naturally be 
expected: but we refrain at present from offering an opinion 
on the nature of such groups, dependant, as they must 
be, on greater anatomical knowledge than we yet possess. 
Nevertheless, until more direct analogies are discovered, 
than those here stated, we feel some confidence in employ- 
ing them as typical distinctions of the two great divisions 
of Gastropod Mollusca. 
