TONNIDAE 199 



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 



