24 Shells as evidence of the Migrations. 
skeins are taken in boats by the fishermen along the coast 
northward, where suitable habitats of the cavaco/ or sea- 
snail are visited. “Slipping a skein over his left wrist, 
the fisherman wrenches one sea-snail after another from 
the wet rocks, blows on it, causing it to exude the dye- 
stuff, which resembles a milky froth, and then dabs the 
cotton thread with numerous shells in succession, until it 
is thoroughly saturated. When each shell had yielded its 
small supply of liquid dye, some fisherman pressed it to 
the rock and waited until it adhered thereto, but others 
laid the shell in a pool. When treated thus the same 
shells yielded a second, though diminished supply, when 
the rocks were visited on the return journey” (pp. 
309-370). 
The late Professor von Martens, in a paper read 
before the Berlin Anthropological Society on October 
22nd, 1898,“ deals very thoroughly with the subject of 
purple dyeing in Central America. In this valuable con- 
tribution he discusses the evidence as to whether the 
employment of the shell-fish for dyeing purposes was an 
independent and precolumbian invention of the Indians, 
or was introduced by the Spaniards. He rightly con- 
cludes that it was practised in America in pre-historic 
times. 
Through Professor Edward Seler, Professor von Mar- 
tens obtained information of the Tehuantepec industry, 
and was shown not only a purple skirt, which the Zapote- 
can women wear only on special occasions and which but 
few can afford, but also kerchiefs with purple stripes such 
as are worn by the Huave Indians, to the south-west of 
Tehuantepec. 
Professor von Martens found, on examining some of 
“* Verhand, Berliner Gesell. fir Anthrop. Ethnol, u. Urgesch., 18908, 
pp. 482-6, 
