The Shell-Collector’s Handbook. 15 
these openings is a large pear-shaped sac—the dart 
sac—which contains a calcareous spicule called the 
spiculum amoris or dart. The shape of the dart 
varies in different species, and the reader wishing to 
learn more about its various modifications may 
consult the papers of Mr. Ashford, in the past 
numbers of the “ Journal of Conchology.” But what 
function these darts may serve is an _ unsettled 
question. It is, however, a certain matter, that 
before two snails engage in coitus they discharge their 
darts at each other, and that the one strives to evade 
the dart of the other. Possibly they are used as an 
amorous greeting. But my friend, Mr. W. Collinge, 
in a paper on “ The Darts of the Helicide,” which he 
read before the Leeds Naturalists’ Club and Scientific 
Association, on October 24th, 1887, considers them as 
degenerate weapons of defence, which, in former ages, 
were probably much stronger and oftener used—and 
doubtless he may, in some measure, be correct. 
During coition, one snail exchanges its spermato- 
phore with the other, and these become lodged in 
the receptaculum seminis of each other, where they 
break up again into spermatozoa, and fertilise the 
ova as they are coming down the oviduct. 
The eggs are laid in a string, which is called the 
nidamental ribbon, or enclosed in horny capsules. 
