ORDER TRACHELIPODA. 37 



in handkerchiefs that have heen washed more than forty 

 times, only it will be somewhat alloyed from^ what it 

 was after the first washing." 



Some years after this, Reaumur discovered great num- 

 bers of a species of buccinum, on the coast of Poitou, 

 and the stones, round which they had collected, were 

 covered with small oval masses, some of which were 

 white, and others of a yellowish colour ; and, having 

 squeezed some of them on the sleeves of his shirt, in 

 about half an hour he found it stained of a fine purple 

 colour, which he was unable to discharge by washing. 

 In repeating his experiment on his return home, he 

 found it was necessary that the cloth should be exposed 

 to the direct rays of the sun. 



The difficulty of procuring and preserving a sufficient 

 number of these shell-fish, must always render the use 

 of this dye very hmited ; but Dr. Bancroft is of opinion, 

 that it might still be rendered beneficial in staining or 

 printing fine muslins, for which purpose but little colour- 

 ing-matter is required. No substance, he remarks, will 

 afford a substantive purple of equal beauty and durabi- 

 lity, and capable of being applied to linen or cotton with 

 so much simplicity and expedition. 



Family A LATA. 



This family is distinguished, by having a canal of va- 

 riable length at the base of its opening, and by the fact 

 of the right margin of the shell changing its form during 

 the growth of the animal. 



The Spotted Scorpion Shell, {Pterocera scorpio.) 

 This curious shell is found in the East Indian seas, 

 and attains a considerable size, as much as six inches. 



