Micronesian Gastropods — Demond 
317 
whether M. antiquus obtains nourishment 
directly from the coral or whether it receives 
its food from the surrounding water through 
the open tube. 
Both the primary shell and its tubular ex- 
tension are calcareous and chalky white. The 
primary shell is typically about 1 inch long; 
the tube may be as long as 6 inches. 
The recent Micronesian collections contain 
only two specimens, taken alive in 5 to 10 
feet of water from the lagoon off Managaha 
Island, Saipan. They were obtained from a 
solid head of living Goniastraea retiformis 
(Lamarck) by breaking open the coral. 
GEOGRAPHIC RANGE: USNM records are 
from Mauritius, Ceylon, Cocos-Keeling Atoll, 
Java, southern Japan, and Saipan only. Re- 
ported from northern Australia and from Ha- 
waii. M. antiquus is probably more abundant 
than the above records indicate but has rarely 
been collected because of its inconspicuous 
mode of life. 
Genus Magilopsis Sowerby, 1919 
Magilopsis lamarcki (Deshayes, 1863). 
Hirase and Taki (1951) pi. Ill, fig. 18 [as 
Leptoconchus lamarkii Deshayes]; Tinker 
(1952) p. 104, 3 figs, on p. 105 [as Lepto- 
conchus lamarkii Deshayes]. 
Uncommon ■ in collections, probably be- 
cause it lives embedded in coral and, conse- 
quently, has been overlooked. The shell of 
M . lamarcki is thin, elongate, characteristic- 
ally chalky white, and about an inch long. 
Unlike Magilus antiquus , it does not secrete a 
tube. 
Among the specimens studied, one was 
collected by Morrison at Eniwetok, slightly 
below low tide line on the leeward lagoon 
reef flat. He reports that Af. lamarcki occurs 
in burrows in living coral, oriented apex 
down. The burrows have only a small open- 
ing at the coral surface, like the holes of 
boring clams of the genus Lithophaga. At 
Raroia Atoll, in the Tuamotus, Morrison 
found the commensal clam Barclayia incerta 
(Deshayes) living in the same burrow with 
M. lamarcki. They were embedded at the base 
of coral (. Acropora spp.) on the leeward ocean 
reef flat. Specimens from Saipan were em- 
bedded, apex down, in slightly irregular bur- 
rows in living Goniastrea retiformis Lamarck. 
A single dead specimen was found at Onotoa 
on living coral in 5 to 20 feet of water in a 
pass through the leeward reef. USNM speci- 
mens from Hawaii, collected by Ditlev Thaa- 
num, were taken from a depth of 150 to 300 
feet off Waikiki. They also were embedded 
in coral. Thaanum observed that the shells 
were unattached but the burrows were so nar- 
row the mollusks could not turn within them. 
The eggs of M. lamarcki are laid in capsules 
and remain within the parental burrow until 
they hatch into pelagic larvae, which even- 
tually settle on coral and form their own 
chambers. 
geographic range: Collection records for 
M. lamarcki are few, but they indicate a wide- 
spread occurrence in the Indo-Pacific. USNM 
specimens are from Mauritius in the Indian 
Ocean and from the Mariana, Marshall, Gil- 
bert, Hawaiian, and Tuamotu islands in the 
Pacific. The species is reported also from 
southern Japan and Formosa. 
Family COLUMBELLIDAE— Dove Shells 
Genus Columbella Lamarck, 1799 
Columhella turturina Lamarck, 1822. 
Kira (1955) pi. 28, fig. 6. 
Characteristically about one-half inch long 
with a yellow or whitish exterior, a white 
aperture, and pink outer and inner lips. 
Lives on small lagoon reefs at depths of 10 
to 30 feet. Two specimens in the recent Mi- 
cronesian collections were found living on 
colonies of Seriatopora sp. 
GEOGRAPHIC range: USNM records are 
from Ceylon and Cocos-Keeling Atoll east- 
ward to Hawaii and Samoa, and from southern 
Japan south to northern Australia and the 
Loyalty Islands. Uncommon in Micronesia. 
