366 
REPRODUCTIVE ORGANS — GYPSOBELUM. 
feminine excitatory organ, perhaps derived from some earlier form 
from which originated tlie diversely constituted egersidia of the 
Stimulatory functions are, however, not 
strictly confined to special egersidia, as the male 
organ may itself hear at its apex a vibratile 
appendage whose function is probably of an 
excitatoiy character. 
The Gypsobelum (yv'pov, lime; fieXos, an 
arrow), love-dart, or Spiculum amoris, is essen- 
tially a feminine stimulatory organ, and is a 
slightly riexible, straight, curved, or even slightly twisted glistening- 
white weapon, formed principally of carbonate of lime, and becoming 
fragile and brittle when dry ; its free end terminates in a fine point, 
and the enlarged base fits upon a conical tubercle at the bottom of 
the ilart-sac. 
The dart is formed very rapidly, the process usually occupying less 
than a week; the shaft first a])poars as a slender spicule attached to 
the apex of the tubercle, increasing simultaneously in length and 
breadth, the blades which are moulded by the 
walls of the sac being next formed, the conical 
base and annulus being the last to be finished, 
these are sometimes composed of numerous 
longitudinal calcareous rods, resembling a 
cricketer’s leg-guard, and crenulate at top and 
bottom, the tubercle having corresponding 
sulci, and projecting into the expanded base 
of the dart. 
The mode of usage of the dart does not yet seem to be universally 
known; the old writers considered it to be a missile hurled by one 
snail at another, and this mode 
is still spoken of by some modern 
writers, as though the dart was 
launched through the air and 
buried in the tissues of the com- 
panion snail. The dart is fitted 
upon the tubercle, attachment 
being assisted by a viscid secretion which extends within the hollow 
shaft of the dart itself, the dart being exserted for use by the eversion 
Fig. 071.— Partial dissection of //c/i.r aspersa 
Miill., showing portions of love-darts of previous 
partners which have become lodged in the viscera. 
Fig. 670. — Annulus of 
dart of lli’li.v aspersa 
Mull., X 3, with adherent 
viscous secretion as left 
after the loss of the dart. 
various genera. 
i 
Fig. 060, — Terminal part 
of male organ of Planorbis 
fi7r//^/^,y(L.),greatly enlarged 
(after Moquin • Tandon ), 
showing the vibratile stimu- 
latory appendage. 
