SOME STRANGE MARRIAGE-CUSTOMS 271 



of its journey. Speedily, no doubt, it become* absorbed, 

 the material being then available for the formation of a 

 new dart. 



This remarkable instrument, which is known as a 

 " Love-dart," or Spiculum amoris, assumes a different 

 form in each species in which it occurs. In some the 

 shaft is ridged like a bayonet, as in the case of the Garden 

 Snail, in others the form assumed is that of an awl. 

 These darts are formed within a special receptacle, or 

 ** dart-sac," but so far no explanation as to the origin 

 of these remarkable structures has even been hinted at. 

 They do not seem to have been derived by the modi- 

 fication of some pre-existing organ serving a different 

 function, as wings, for example, are derived from walking 

 limbs, or as lungs are derived from air-sacs. Their 

 origin is as mysterious as their use : for they are not 

 found in all Snails, though they occur in one or two Slugs 

 — which are degenerate Snails. But no other Molluscs 

 save the Snails and one or two of their immediate allies 

 are so armed. 



The hermaphrodite conditions of these animals, as 

 with other Mollusca in like case, present some knotty 

 points for consideration, and especially in regard to the 

 problem of sex-attraction. Where each individual is 

 as much male as female, which is the dominating factor 

 in desire, the maleness or the femaleness ? Though 

 each individual contains both ova and sperm cells, 

 probably these ripen at different times, to avoid danger 

 of self-fertilization. In this case the sex impulses are 

 on the same footing as in the case of animals wherein 

 the sexes are not thus combined. That is to say, the 

 individual which is for the moment only potentially male 

 mat«8 with another for th* moment only potentially 



