854 
subordinate families,from prominent cha- 
racters in the animals themselves, nothing 
remained but to observe the ‘different 
forms of these external coverings, and to 
examine how far they were capable of 
being reduced to some kind of regular 
order. 
Mr. Montague has adopted the Lin- 
nean arrangement, with a few variations 
and improvements; and if it be not su- 
pereminently the best, it appears to be as 
natural and easy in practice, as any 
which has hitherto been formed. But 
though with Linnzus he has taken his ge- 
neric characters from the form and struc- 
ture of the shells, he has by no means 
lost sight of the animal inhabitants. 
Indeed, whenever it is possible, they 
should always be considered as strictly 
and naturally connected. The shell is 
not merely the habitation of an orga- 
nized being ; it is part of the being itself ; 
formed from its substance ; inseparably 
attached to it while it continues to live, 
and powerfully affecting its general ha- 
bits and economy. Wemay, therefore, 
justly presume that the form and struc- 
ture of the.one will afford the best key 
to the essential characters of the other. 
It is acknowledged that “ few of the 
Linnean genera of testacea are wholly 
inhabited by the same animal.” Nor is 
it at all surprizing that two professedly 
artificial distributions, founded exclu- 
sively on separate and those far from 
primar; characters, should not perfectly 
coincide. To form a truly natural ar- 
rangement,the conchologist must look be- 
yond the cutline of an aperture and the 
construction of a hinge: he must inves- 
tigate the natural connection of a mul- 
tivalve, of a trivalve, and of a univalve 
structure ; of a fixed and of a moveable 
position ; of a turbinated and not turbi- 
nated form, with a peculiar inward phy- 
siology and an external mode of life. 
Such an analogy will, we doubt not, one 
day be found: and though the complete 
discovery may be far distant, every step 
towards it, and every attempt to make 
the first step, is worthy of praise, and 
will not be without its due reward. Lin- 
‘meus has referred most of the testa- 
ceous vermes to some of the gene- 
ra of his order mollusca,~or vermes 
without a testaceous covering ; and tho’ 
he was far from supposing that each of 
his artificial genera of shells had a pecu- 
liar corresponding mollusca, he seems to 
have taken it for granted, that. all the 
species of each particular genus are of 
the same kind. T'o his two genera of 
NATURAL HISTORY. 
multivalves, chiton and lepas, hehas as- 
signed respectively the doris and the 
triton. Of the bivalves, he has assigned 
to the pholas, the mya and the solen, an 
ascidia; and also to the mytilus, but 
with a mark of doubt: to the tellina, 
the cardium, the mactra, the donax, the 
venus, the spondylius, the chama, andthe 
ostrea, he has assigned a tethys; and 
also to the arca, but with a mark of 
doubt: to the anomia, an unnamed 
mollusca, and to the pinna, a limax. 
Of the univalves, he has assigned to the 
argonauta, a sepia; to the nautilus, an 
unnamed mollusea; to all the rest, ex- 
cept the dentalium, the serpula, the te- 
redo, and the sabella, a limax; to the 
three former of these, a, terebella ; and 
te the last, anereis. With the generic 
characters of these, translated from the 
Systema Nature, Mr. Montague has 
very properly introduced his work, and 
has added the spio and the amphitrite, 
formed since the time of Linneus. He 
has also subjoined Muller’s arrangement 
of a6 testacea by their several ani- 
mals. 
In the genus chiton, Mr. Montague 
has added to those of Pennant in the 
British Zoology, and of Da Costa, the 
cinereus, the albus, and the fascicularis 
of Linnzus; and the ‘septemvalvis, a 
nondescript: but has given no informa- 
tion with respect to the animal. 
The genus lepas, Mr. Montague, fol 
lowing Dr. Pulteney, has divided into 
two, as not possessing any similitude, 
except in that of the animal inhabitant. 
Those of the sessile kind he terms ba- 
lanus, and continues the pedunculated 
ones under their original title. Thenew 
British species of balanus are the rugos 
sus of Pulteney ; and the conoides of Do- 
novan. ‘To the anatifera, the only pro- 
per species of lepas in Pennant,are added, 
the anserifera ‘and scalpellum of Linneus, 
the fascicularis of Ellis, and the sulcata, a 
new and elegant species found on Gor- 
gonia Flabellum, near Portland Island. 
The lepas seems a connecting link 
between the balanus and the mollusca 
genus triton, the only known species of 
which inhabits the clefts of submarine 
rocks. The animals in all the genera 
are fixed, and appear to have the same 
general habits, the approximating sides 
of the rock affording to the triton lito- 
reus a defence, and performing the of- 
fice of a shell. x 
The pholas has received no addition to 
Pennant’s British species, but the striatus 
