even to the nmnber of rilas. 



The above species are reprr.sentatlves of a group is typified 

 "by the recent '.Vest Indiaii form "-■■' which the earliest name probab- 

 ly is 0_. Ic uoostonu"'.!]! 3orn, but which '. ' ly name"? narmore'Tin 



fl). Tab:., i.-io. Caes. Vind ., . , ". ', . . G, 1R70. 



lamarck iZ) or subelongatum So'-rrby f5). ;ent sr^ecies has 



narrower and more ■" ■ -"-■-■-- ribs. 



( ?) . Anim. s.:. ' - ; . , 



ic). Prcc. Zool. 3oc. London for 1840, p. 



This S"ieoies is named for Dr. T. ./ayland Vaughan, Chief 

 of the Division of Coastal "^lain Invest i"-ation of the United 

 States Geological Survey, ;-r ui. . .-- ::: "'''- investi- 



gation of the V/est Indian region is progressinp- rapidly, 



Ooci-rrenee.- Iov;er Iliocene: Bowdc -, v-ui., Janiaica. 



