126 WHITEAVES ON MARINE INVERTEBRATA, ETC., 
concentric lines of growth. Central areas of all the valves but the anterior one 
regularly pitted, as viewed by an ordinary simple lens of moderate power, the 
pitting being most distinct near the suture. These pits are the interstices between 
longitudinal, lightly curved and convergent raised lines, and the curved raised 
lines of growth. Lateral areas of the valves (exclusive of the anterior one) not so 
distinctly pitted, but more or less marked with faint radiating striae, especially 
those of the anterior portion of the shell; those of the third to the seventh, both 
inclusive, each bearing from four to six distant, isolated, prominent and rounded 
tubercles on each side, three being usually placed on each of the lines which 
separate the lateral from the central areas. 
Length of the only specimen collected, about fourteen millimetres ; maximum 
breadth of the same, six and a half. 
Discovery Passage at station No. 7, one living specimen. 
An interesting and beautiful little species, apparently well characterized by 
the peculiarly punctate surface of the central area of the valves. 
TONICELLA LINEATA, Wood. (Sp.) Frequent, living, at low water, on the north shore of 
the Strait of Georgia, in Malaspina Inlet, Discovery Passage, Race Passage in 
Johnstone Strait, Queen Charlotte Sound, and on the north and north-west coast 
of Vancouver Island, from Nahwitti Bar to Quatsino Sound. Taken abundantly 
from the stomach of a harlequin duck -(Histrionicus torquatus) shot at Mittlenatch 
Island, in the Strait of Georgia. Dredged also in Queen Charlotte Sound at station 
No. 12. 
ISCHNOCHITON INTERSTINCTUS, Gould. (Sp.) Low tide in Race Passage Johnstone Strait, 
and in Queen Charlotte Sound, but apparently not common. More abundant in 
Discovery Passage at station No. 7, in Johnstone Strait at station No. 10, in Queen 
Charlotte Sound at stations Nos. 12, 14, 15 and 16, and in Quatsino Sound at 
station No. 20. 
ISCHNORADSIA TRIFIDA, Carpenter. (Sp.) Queen Charlotte Sound, one large, living 
specimen. 
LEPIDOPLEURUS MERTENSII, Middendorf. (Sp.) Discovery Passage at station No. 7, two 
living specimens; and Queen Charlotte Sound at station No. 15, one living 
example. 
Acm@a (COLLISELLA) PATINA, Eschscholtz. Abundant, living at low tide in Johnstone 
Strait. 
ACMÆA (CoLLISELLA) PELTA, Eschscholtz. Common and alive at low tide at the north end 
of Texada Island, Strait of Georgia; in Discovery Passage, between Seymour Nar- 
rows and Elk Harbour; in Johnstone Strait; on the east side of Queen Charlotte 
Sound ; and along the north and north-west coast of Vancouver Island, from Nah- 
witti Bar to Quatsino Sound. Numerous but dead specimens were dredged in 
Discovery Passage at station No. 7. 
ACMÆA (COLLISELLA) PERSONA, Eschscholtz. Low tide in Discovery Passage, between 
Seymour Narrows and Elk Harbour, four adult, living specimens. 
