144 TH E LIFE OF THE MOLLUSCA 



frequently the cause of poisoning when eaten. 

 Limncea truncatula, as already stated (ante, p. 79), 

 is the intermediate host of the Liver Fluke of Sheep. 



The mischief that Slugs and Snails can work to 

 crops and in gardens is only too well known ; the 

 former are also said to damage corks. 



The amount of mischief that has been caused by 

 the Ship-worm (Teredo) is almost incalculable, but 

 with the passing of the wooden ship and the ex- 

 tensive use of iron and steel work for piers, its 

 destructive energies are now mainly confined to 

 the timber work of groynes and landing-stages. 

 There it is still the despair of the engineer, for no 

 known method of treating the piles will keep the foe 

 at bay. 



The prices paid by collectors for fine specimens of 

 rare shells, although at one time considered high, 

 are insignificant beside those given of late years for 

 scarce postage stamps. Thus £43 10s. was paid in 

 1854 for a Conns gloriamaris, and £42 in 1865 for 

 another example. The latter figure was also realized 

 the following year for a specimen of Cyprcza guttata, 

 and £40 for a C. princeps, while as much as £100 is 

 said to have been given for a single specimen of the 

 heteropod Carinaria, now worth only from £5 to 

 £10. Of late years the highest sum paid for a single 

 shell was that given for the magnificent Plenrotomaria 

 Adansoniana, now in the Natural History Museum, 

 for which the original vendor obtained £55. 



