170 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 37. 
Shell small, white or pale brownish inside and out, of the same gen- 
eral form as the last species; smooth, or faintly striated; length 
about 25 mm. 
This is not the P. callaoénsis of Blainville, 1832. It is too smalla 
shell to have much economic importance and does not seem to be 
abundant. Tryon referred it wrongly to the genus Coralliophila, 
probably from figures or worn specimens; but it is quite destitute of 
the peculiar sculpture of Coralliophila. 
THAIS DELESSERTIANA Orbigny. 
Purpura delessertiana OrpiaNy, Voy. Am. Mér., vol. 5, 1841, pp..ix, 439, pl. 77, 
1s Te 
Caracolitos. Callao Bay, on the shores of San Lorenzo Island; on the Callao water 
front; and common on the shore rocks at the Chincha Islands. 
Distribution.—Cedros Island, west coast of Lower California, and 
southward to the Chincha Islands. 
Shell of the same general shape as 7. chocolata Duclos, but smaller, 
thinner, with a smoother and more polished surface, the shoulder of 
the whorls more sloping and less prominently tuberculose, or without 
tubercles; general color brownish, usually with one or two paler, 
narrow, spiral bands on the last whorl; length about 50 mm. 
This is Purpura callaoénsis Blainville, 1832, not of Gray, 1828. 
THAIS KIOSQUIFORMIS Duclos. | 
Plate 22, fig. 4. 
Purpura kiosquiformis Ductos, Ann. d’Hist. Nat., May, 1832, pl. 1, fig. 5.— 
KiENER, Icon., Purpura, p. 59, pl. 15, fig. 40. 
Caracoles. Mouth of the Tumbes River. Also from the oysters of Matapalo, grow- 
ing on the mangrove shoots. Near Capon, from the Estero Zarumilla, opposite Estero 
Cascajal. 
These oyster drills are of importance economically as being a serious enemy to the 
young oysters. Also as of use in making a purple dye which is considered permanent. 
It is said that this forms a small industry in Ecuador. The purpuriferous gland is 
extracted and mixed with lemon juice to prepare the dye. ‘The flesh of the animal is 
also preserved for food. 
It is said to be customary to take thread from the region of Sechura and Piura to 
Guayaquil, to be dyed and returned, when it is used in fancy alforjas and other hand- 
woven articles. The dyed thread is called ‘‘hilo de caracoles” by the natives. 
I saw a neat alforja hand-woven chiefly from hand-spun thread. It was in four 
colors: Natural white cotton and natural brown cotton, the purple hilo de caracoles, 
and an imported thread. 
These drills were commonly found (Jan. 23) in pairs, breeding. Their destructive 
work on the young oysters is erroneously attributed by the local fishermen to an isopod, 
which is found boring into the mangrove roots. 
Distribution.—From Magdalena Bay, Lower California, south to 
Tumbes, Peru. 
Shell turrited, whorls more or less tabulate above the shoulder, in 
front of which there are one or two strong, more or less tuberculose 
