Page:American Seashells (1954).djvu/249

Rh Subgenus Crossata Jousseaume 1881

Bursa califorfiica Hinds Californian Frog-shell Plate 2or

Monterey, California, to the Gulf of California. 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. Com- mon offshore, occasionally washed ashore. A scavenger.

Family TONNIDAE Genus Torma Briinnich 1772

Toiina maculosa Dillwyn Atlantic Partridge Tun Plate gd

Southeast Florida and the West Indies.

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. Do Hum 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 Plate 2^{

North Carolina to Florida, the Gulf States and the West Indies.

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 Plate 2 3g

Ofl^ New Jersey to the Lesser Antilles.

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