CHAP. XXIL] MOLLUSCA. 507 



CLASS. GASTEKOPODA. 



Order L PRO SO BE ANC HI AT A. 



FAMILY 1. STKOMBID^E. (4 Genera, 86 Species.) 



DISTRIBUTION. The Strombidse, or Wing-shells, inhabit tropi- 

 cal and warm seas from the Mediterranean to New Zealand ; most 

 abundant in the Indian and Pacific Oceans. There are nearly 

 200 fossil species, from the Lias to Miocene and recent deposits. 



FAMILY 2. MUKICID.ZE. (12 Genera, 1000 Species.) 



DISTRIBUTION. All seas, most abundant in the Tropics. 

 Trichotropis is confined to Northern seas ; Murex and Fusus are 

 cosmopolitan. There are about 700 fossil species, ranging from 

 the Oolite to the Miocene and recent formations; 



FAMILY 3. BUCCINID^. (24 Genera, 1100 Species.) 



DISTRIBUTION. The Buccinidse, or " Whelks," range over the 

 whole world, but some of the genera are restricted. Buccinum 

 inhabits the north and south temperate seas; Monoceros the 

 West Coast of America ; Cassidaria the Mediterranean ; Phos, 

 Harpa, JEburna, and Ricinula, are confined to the Pacific ; Dol- 

 ium inhabits the Mediterranean as well as the Pacific. There 

 are about 350 fossil species, mostly from the Eocene and Miocene 

 beds. 



