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TONNIDAE 199
Subgenus Crossata Jousseaume 1881
Bursa califorfiica Hinds Californian Frog-shell
Monterey, California, to the Gulf of California.
Plate 2or
3 to 5 inches in length, moderately heavy, tan-cream in color and with
about 6 whorls, each of which has 2 varices, one opposite the other. The
last varix has 4 to 5 large nodules; in the spire only one nodule shows. Be-
tween the varices there are 2 stout spines. White aperture with a posterior
canal almost the size of the anterior (siphonal) canal. Lip crenulate. Common
offshore, occasionally washed ashore. A scavenger.
Family TONNIDAE
Genus Torma Briinnich 1772
Toiina maculosa Dillwyn Atlantic Partridge Tun
Southeast Florida and the West Indies.
Plate gd
2 to 5 inches in length, thin but strong. Nuclear whorls golden-brown
and glassy-smooth. Periostracum thin and usually flakes off in dried specimens.
DoHum album Conrad is only an albino form. Tonna perdix Linne is not
this species, but an Indo-Pacific shell which has a more pointed spire, clearer
squares of color and fewer spiral ribs. Our species is fairly common, espe-
cially in the West Indies. Adults do not have an operculum in this genus.
Tonna galea Linne Giant Tun
North Carolina to Florida, the Gulf States and the West Indies.
Plate 2^{
5 to 7 inches in length, thin but rather strong, although the lip is easily
broken. Ground color whitish to light coffee-brown, sometimes slightly
mottled. With 19 to 21 broad, flatfish ribs. This species also occurs in the
Mediterranean and the Indo-Pacific. The subspecies, brasiliana Morch, known
only from Brazil, has a pushed-down, flattish spire. Not uncommon below
low water.
Genus Eudolium Dall 1889
Eudoliu7n crosseanum Monterosato Crosse's Tun
Ofl^ New Jersey to the Lesser Antilles.
Plate 2 3g
2 to 3/4 inches in length, moderately thin-shelled, but strong. Each of
the 6 whorls bears numerous, spiral ridges and fine threads. Nuclear whorls