1918] Packard: Molluscan Fauna from San Francisco Bay 321 
Carpenter (1863) and subsequent writers have listed this species in 
association with the larger form previously considered. <A single 
weathered specimen was obtained by the dredge in 18 fathoms of 
water. The distribution of the living shell is very general occurring 
upon rocks or piles at or just above the reach of the waves along the 
shores of the entire bay as well as those outside the Golden Gate. 
Range.—Sitka, to Cape San Lueas, Lower California (Orcutt). 
Lacuna Turton 
Lacuna porrecta Carpenter 
Lacuna porrecta Carpenter (1863), p. 656; (1864b), p. 429; Arnold, R. 
(1903), p. 303. 
Description.—Arnold (1908) described this species as follows: 
‘*Shell small, white; spire not much elevated; whorls three, convex; body- 
whorl very slightly angulated; suture distinct; aperture ovate; lip effuse; 
umbilical chink large. ... Distinguishable by large umbilical chink, depressed 
spire, large angle at apex, and effuse outer lip.’’ 
Height, 2 to 4 mm. 
Occurrence.—At stations D 5731 (3), D5797* (1). 
Wood and Raymond (1891) found this small gastropod within San 
Francisco County. It has been obtained by the Survey at two dredg- 
ing stations, one being outside the Golden Gate in 16 fathoms on a sand 
and gravel bottom and the other, within the middle division of the 
bay in 81% fathoms on a pure sand bottom. 
Range.—Vancouver Island, B. C., to San Francisco, California. 
Lacuna unifasciata Carpenter 
Lacuna wnifasciata Carpenter (1856d), p. 205; (1863), p. 656; Keep (1911), 
p. 205. 
Description—kKeep (1911) described this small littoral species as follows: 
‘* Externally it is brown and glossy, with the color broken into dots on the 
keel of the body-whorl. The aperture is semi-lunar in shape, and the flattened 
columella has a small umbilical fissure from which circumstance it receives its 
generic name.’’ 
Height, 2 to 3 mm. 
Occurrence. — At Bonita Point* (8), and questionably at the 
Presidio. 
This species is recorded from this region by Carpenter (1863) and 
by subsequent writers. Obtained by the Survey only at the shore 
station at Bonita Point. 
Range.—Farallon Islands to San Diego (Carpenter). 
