MOLLUSCA. 95 
lowing remarks concerning the multilocular testacea have 
been extracted. The multilocular testacea may be divided 
into three sections ; the first including those which are ob- 
viously spiral ; the second, those which are produced ; and 
the third, those which are of a globular or lenticular form. 
These sections are merely provisional, and are only intend- 
ed to render more obvious and intelligible our notices of 
the genera. 
1. The spiral multilocular testacea. At the head of this 
first division stands the modern genus NauriLvs, in which 
the turns of the spire are contiguous, and the last whorl in- 
closes the others. The partitions are perforated by a tube. 
We possess on our shores several species of this genus, of 
which the WV. crispus is the most common. 
In form, the genus LENTICULINA is nearly related to the 
former. The margin of the mouth reaches to the centre 
of the shell on both sides, and the partitions are destitute 
of asyphon. Lamark is in possession of a recent shell of 
this species from the sea near Teneriff. 
The shells which Mr. Sowerby, in his Mineral Concho- 
logy, has figured under the genus Eiurpsoxitues, have the 
whorls conspicuous, although the mouth clasps the body 
whorl. But it is easily distinguished from the other genera 
with which it is related by its elliptical form. 
The genus Discorsis of Lamark (formerly called by him 
Planulites) bears a considerable resemblance to the nauti- 
lus in form, but the whorls are all apparent, and the parti- 
tions entire. 
In the genus RoTA.tra, the spires approach to a conical 
shape, and the marginated trigonal aperture is reflected to- 
wards the base of the shell. It consists of shells which are 
now found in a fossil state. 
