336 University of California Publications in Zoology [Vou.14 
Description.—Tryon has described this species: as follows: 
“‘Usually light brown or yellowish, rarely with several revolving indistinct, 
rufous bands. Within the aperture varying from light flesh-color to dark 
salmon, chocolate or purple.’’ 
Height, 6 to 27 mm. 
Occurrence—At stations D5781 (17, 18), D5782 (6), D5783 
(17, 1), D 5784 (11, 9), D5795 (1), D5810 (12), D5811 (2, 12), 
D 5812 (1, 2), D 5813 (2), D 5814 (4, 8), D 5847 (2), and questionably 
at D 5773. 
Stearns (1894) was the first to recognize this exotic species within 
San Francisco Bay. This is the oyster drill, which plays so much 
havoe on the oyster beds. It is abundant in the lower division of the 
bay in the vicinity of Poimt San Mateo. Living specimens were 
dredged in 1 to 4 fathoms from bottoms composed of mud and shells. 
Range.—Known on the Pacific Coast only in the vicinity of the 
beds of Ostrea elongata. Maine to Florida (Tryon). 
THAISIDAE Dall 
Thais Bolten 
Thais lamellosa (Gmelin) 
Plate 40, figures 1, 2, 3, 4, 5, 5a, 6, 7, 8; plate 59 
Buccinum lamellosum Gmelin, Linnaeus (1788-1793), p. 3498. 
Purpura crispata Chemnitz, Carpenter (1863), p. 662; Arnold, R. (1903), 
p. 261. 
Thais (Nucella) lamellosa, Dall (1915a), p. 563. 
Description—The following is Arnold’s (1903) description of this species: 
‘Shell fusiform, thick; spire elevated; apex subacute; whorls five to seven, 
convex or angulated, with one or more prominent spiral ridges on angular part 
of whorl; suture impressed, distinct; aperture ovate to elliptical; outer lip 
effuse, generally denticulate; inner lip incrusted, smooth; canal short, curved 
backwards; umbilicus subperforate.’’ 
Height, 4 to 60 mm. 
Occurrence —At stations D 5700 (10, 5), D 5701 (1), D 5702 (39, 
24), D 5708 (10, 24), D 5714 (2,12), D 5723 (14), D 5724 (1), D 5737 
(2), D 5753 (1), D5755 (1), D 5773 (4, 7), D5775 (3), D5779 (2), 
D 5781 (3), D5795 (6, 23), D5796 (2, 27), D5800 (13), D5801 
(6, 8), D 5802 (1), D 5808 (7, 17), D 5809 (2, 45), D 5812 (2), D 5821 
B (2), D5823 A (1), D5824 B (425), D5825 (1), D 5825 B (1), 
D 5826 (2), D5826 A (60), D5826 B (10), D5827 (18), D5827 A 
(21), D 5827 B (7), D 5828 B (7), D 5829 (1), D 5829 A (40), D 5831 
(1), D 5832 A (3), D 5833 (14), D 5834 (1), D 5841 (13), D 5843 (2), 
Red Rock (53, 14), Sausalito (2), and questionably D 5712, D 5731, 
D 5732, D 5736, D 5797, D 5798. 
