Geographical Distribution of the Shell-Purple Industry. 23 
duity of the Indians. It is taken to the sea-side, when a 
sufficient number of shells are collected, which being 
dried from the sea water, the work is commenced. Each 
shell is taken up singly, and a slight pressure upon the 
valve which closes its mouth [operculum] forces out a 
few drops of the colouring fluid, which is then almost 
destitute of colour. In this each thread is dipped singly, 
and after absorbing enough of the precious fluid, is care- 
fully drawn out between the thumb and finger, and laid 
aside to dry. Whole days and nights are spent in this 
tedious process, until the work is completed. At first the 
thread is of a dull blue colour, but upon exposure to the 
atmosphere acquires the desired tint. The fish is not 
destroyed by the operation but is returned to the sea 
when it lays in a new stock of colouring matter for a 
future occasion.” 
In connection with the Nicoya industry, the observa- 
tions of C. V. Hartman” are interesting. On one of his 
recent expeditions to the Pacific Coast of Costa Rica, he 
visited Guanacosta, where he saw an Indian woman from 
Chiriqui wading in the water in search of Purpura. She 
would put the shell to her mouth and blow into it, causing 
the snail to discharge a greenish yellow fluid, which she 
applied to white cotton thread. The fluid in drying turns 
to purple. 
An even more interesting account of the existence of 
purple dyeing in the New World is that recently published 
by Zelia Nuttall, viz., “ A curious survival in Mexico of 
the use of the Purpura shell-fish for dyeing.”* In this 
paper an excellent description is given of the dyeing of 
cotton thread for the manufacture of purple skirts worn 
by the women of Tehuantepec. In the spring the cotton 
‘* See Mac Curdy, of. cz?¢., p. 160, quoting Hartman. 
** Putnam Anniversary Volume, 1909, pp. 368-384. 
