The Shell-Collector's Handbook. 5 
careous salts (epiphragm, hypophragm, hybernaculum or 
clausilium) which has recently been shown by a 
German observer to be a secretion of the liver- 
cells. 
THE Bopy.—The body is usually divided into two 
portions—the one (prostoma) including all in front of 
the mantle edge, the other (metastoma) all behind it. 
That portion of the body habitually contained within 
the shell is often spoken of as the visceral hump. 
This visceral hump is covered by a’tent or roof, 
extremely vascular in character, called the mantle, a 
portion of which is visible externally just below the 
peritreme (collar). 
The body external to the shell presents ten points 
for examination, best seen when the animal is ex- 
tended. In front is a rounded extremity—the head— 
bearing on its dorsal surface two, posterior or dorsal 
tentacles, and two anterior or ventral tentacles, and on 
its lower or ventral surface the mouth bounded by two 
lateral lips and one inferior lip. The dorsal tentacles 
are the longer, and bear at their extremities the eyes. 
Both pairs of tentacles can be inverted into the body 
at the will of the animal. The foot is the large mus- 
cular expansion on the lower surface of the prostoma, 
and.by means of it the animal walks. Below the 
mouth is the aperture of the pedal gland. Behind the 
right lip, and just below the right dorsal tentacle, the 
genital apertwre exists. And in the collar on the 
right side is a large round foramen—the pulmonary 
or respiratory orifice—and closely associated with this, 
a smaller aperture obtains, which is the termination of 
the duct of the renal organ. Below and to the right 
