74 THE NAUTILUS. 



ancestor of Fnlgur, the latter being first represented in the Oligocene 

 and Lower Miocene by F. spiniger and its several varieties, and in 

 the middle Miocene by F. fusifvrmis} 



From this form was probably derived, as Mr, Grabau states, " the 

 large and ponderous Fi'fgur maximum Conr.," which apparently, 

 through the varieties tritnvis and Jilusum,'' leads to the recent F. carica 

 and its variety eliceans. On the otiier hand, the sinistral form un- 

 doubtedly evolved from F. maximum in the upper Miocene much 

 eailier than Mr. Grabau's table would imply, and by forms such as 

 F. adversarium and F. objilosum leads directly to the recent F. perver- 

 sum, and its rare variety kieneri Phil, presenting exact parallels to 

 the F. trilonisjibsum and F. carica eJiceans series, thus strengthening 

 the theory of a common ancestry. During the I'liocene, F. perver- 

 sum seems to have extended and found more favorable conditions 

 further south, for it is really more plentiful and better developed in 

 the Caloosahatchie than in the Waccamaw beds. On the gulf coast 

 at the ])resent time it is more abundant than on the Atlantic, while 

 F. carica is not found at all in the Gulf of Mexico. 



In the Caloosahatchie beds there appeared a new form, F. rapiim, 

 Hi-iip., probably derived from F. penersum (as such forms oi' perver- 

 sum as INIr. Grabau has called vbrapum would indicate) and appar- 

 ently representing a reversion to the 7naximHm type. 



1 would not con^^ider ohrapum to be sinistral rapum, neither would 

 I consider obfi'osum to be a sinistral j^/os«/?t; for while admitting a 

 common ancestry, the immutaliility of the jecent perversum and 

 carica has given us reason to believe that the same stabilily has ex- 

 isted since ihey originated. To admit the mutability of sinistral and 

 dextral forms oidy makes " confusion worse confounded." F. rapum, 

 throiiu'li the form trilonoides Grabau, leads to the recent F. coarcta- 

 tum Sowerby of the Gulf of Mexico, an extremely rare shell which 

 may possibly be extinct. The long anterior canal of the monstrosity 

 F. cand<'lalriim Lam., as figured by Kiener, indicates a position here, 

 rather than under eliceans. 



1 In a bed which overlies the Chipola and having an out-crop in a mill-race 

 two miles east of Argyle, Fla., I found this species, identical with specimens 

 from St. Mary's, Md. 



^F.Jtlosum did not originate in the upper Miocene, as indicated by Mr. Gra- 

 ban's table ; F. viaximiim, trilonis and filosum are all associated with /-''. incile at 

 Yorktown, which moreover is the type locality for filosum. 



