5,% (JEOGRAPHICAL ZOOLOGY. [part i v. 



Family 14.— VENPTtlD^E, (iO Genera, 600 Species.) 



DiSTKiBUTiox. — Universal. Lticijiojjsis is confined to tlie 

 North Atlantic ; Glauconeza to the mouths of rivers in the Orien- 

 tal region ; Meroe and Trigona to warm seas. There are about 

 350 fossil species, ranging back to the Oolitic period. 



Family 15.— MACTRID^E. (5 Genera, 147 Species.) 



Distribution. — All seas, but more abundant in the Tropics. 

 Qii'ithodon is found in the Gulf of Mexico ; Anatiiulla in the 

 Oriental region. There are about 60 fossil species, ranging back 

 to the Carboniferous period. 



Family 16.— TELLINID^:. (U Genera, 560 Species.) 



Distribution'. — All seas ; most abuildant in the Tropics. 

 Galatea is confined to African rivers. There are about 60 fossil 

 species, mostly Tertiary, but ranging back to the Carboniferous 

 period. 



Family 17.— SOLENIDJ^:. (3 Genera, 63 Species.) 



Distribution. —All Temperate and Tropical seas. There are 

 SO fossil species which range back to the Carboniferous epoch. 



Family 18.— MYACID^. (6 Genera, 121 Species.) 



Distribution. — All seas. Fanopma inhabits both North and 

 South Temperate seas ; Glycimeris, Arctic seas. There are near 

 350 fossil species, ranging back to the Lower Oolite formation. 



Family 19.-ANATINID^. (8 Genera, 246 Species.) 



Disteibution. — All seas. Pholadomya is from Tropical Africa ; 

 Myadora from the Western Pacific ; Myochama and Chamostrxa 

 are Australian. There are about 400 fossil species, ranging back 

 to the Lower Silurian formation. 



