164 Mr. Light foot’s Account of 
otherwife he would doubtlefs not have ranked it among th<r 
Helices . 
The place where the fhell is to be found, is in deep ditches 
of clear water, adhering to the roots of Carices . It was col- 
lected near Upton Church, not far from Eton, in Bucking- 
hamfhire, in the fpring feafon. Mr. Walker reports it to be 
found on flags in Hornhill Brooks, in Kent, but very rare. 
The figures annexed will explain what I have been defcribing 
much better than words. 
Fig. 1. (Tab. I.) The fhell of its natural fize, with the 
umbilicated fide uppermoft. 
2. The fame with the deprefled fide uppermoft ; the dark 
fhade in both {hewing how far the cavity of the {hell is occu- 
pied by the dead animal included. 
3. The {hell magnified with the deprejjed fide uppermoft, 
fhewing the live animal within it,/ its head and antenna pro- 
truded. Here the white lines appear double, being the {hade of 
the fepta on both fides of the fhell. 
5. The fame magnified with the umbilicated fide uppermoft;, 
the head and under fide of the animal appearing to view. 
4. The fame magnified in a perpendicular view, with the 
mouth in front, but cut away down to the firft feptum , in 
order to {hew not only the carina or keel of the {hell, but 
more efpecially the exa£t appearance of the triradiated feptum 
neareft the mouth, and in what manner the animal contrives to 
extrude itfelf through the aperture, the head and tail being 
accommodated to pafs through two of the parts of the inverted 
Y (^), while the dorfal ligament occupies the third. 
8. The animars excrement. 
6. 7. Horizontal feftions of the {hell, in order to {hew the 
internal ftrufture, or the appearance of the jepta , when the 
fhell 
