THE NAUTILUS. 



VOL. XX. MARCH, 19O7. No. 11. 



A NEW FOSSIL BUSYCON (FULGUK) FEOM FLOEIDA. 



BY T. H. ALDRICH. 



BUSYCON MONTFORTI n. sp. Plate VI. 



Shell large, solid. Whorls about seven ; those of the spire with 

 slight nodules, which on the body whorl develop progressively into 

 small, medium, and then large spines, ten in number on the specimen 

 figured ; these spines are flattened above, and partly so below, and 

 differ from those of Busycon eliceans Montf., by being filled by the 

 successive growth additions. Surface covered with raised lines, ex- 

 cept on the middle of the body whorl. Aperture within still yellow- 

 ish-brown. Canal contracted and twisted somewhat to the left. 

 Inner lip with a strong callus carrying a fold at the angle with the 

 canal ; outer lip corrugated within. The specimen has the spire 

 slightly broken, but it is probably pointed like Busycon eliceans. The 

 canal is considerably shortened by breakage. 



Locality : Shoal River, Walton County, West Florida. 



Remarks : The geological horizon is in the Upper Oligocene of 

 Dall. This species is especially interesting because it shows that 

 Busycon eliceans Montf. is a distinct form with an Oligocene (?) ances- 

 tor. There are a number of minor differences between the two 

 species, but when placed side by side they show without question 

 their intimate relations. The descent of the group will need to be 

 cousiderably modified to conform to the new discovery. 



