INSTITUTE OF SCIENCE, PHILADELPHIA. 349 



Crucibulum auricula Gmelin. 

 Patella auricula Gmelin, Syst. Nat., p. 3694, 1780. 



The typical form is rather depressed, with fine radiating, frequently 

 dichotomous lines on the upper surface. It is found in the Pliocene of the 

 Waccamaw beds, S. C. , Johnson ; of the Caloosahatchie, Shell Creek and the 

 Myakka River, Florida, Dall and Willcox ; living on the west coast of Florida 

 and southward to Northern Brazil in 25 to 100 fathoms. Some forms of the 

 West American C. spijtosiiin are hardly distinguishable. 



Crucibulum auricula var. costatum Say. 



Dispotcea costala Say, Journ. Acad. Nat. Sci. Phila. iv. p. 132, 1824; Conr., Medial Tert., p. 



So, pi. 45, fig. 2 ; not of Tuomey and Holmes. 

 Calyplrcea pileolus H. C. Lea, Trans. Am. Phil. Soc, 2d Ser. ix. p. 248, pi. 35, fig. 38, 



1845 I young shell. 

 C. verrucosum (Rve.) Heilprin, Trans. Wagner Inst. i. p. 103, 1887. 



This variety has strong radiating ribs without any fine sculpture on them. 

 It is known from the Miocene of St. Mary's River, Maryland ; the Plio- 

 cene of the Caloosahatchie and Shell Creek, Florida, Dall and Willcox ; and 

 living in the Antilles. 



Crucibulum auricula var. chipolanum Dall. 



Shell with sharply cut radiating threads and riblets, rarely dichotomous, 

 stronger than in the typical form, yet not reaching the strength of the ribs in 

 C. costatum. From the Older Miocene of the Chipola River, a mile below 

 Bailey's Ferry, Burns. All the specimens from this horizon appear to have 

 this particular sculpture, which otherwise would hardly have authorized the 

 application to them of even a varietal distinctive name. 



Crucibulum auricula var. imbricatum Sowerby. 



Calyptrcsa imbricata Sby., Genera, xxiii. fig. 5, 1824. 



Dispoiesa ramosa Conr., Medial Tert., p. 79, pi. 45, figs. 3, 18, Jan., 1845 ! Tuomey and 

 Holmes, Pleioc. Fos., p. 108, pi. 25, fig. 5. 



Like C. costatum, but with fine radiating threads over the ribs, frequently 

 irregular or ramose. From the Chesapeake Miocene of Yorktown, Va., Wil- 

 mington, N. C, and Calvert Co., Md. ; Pliocene of the Caloosahatchie beds, 

 Dall ; living on the coast of West America from Lower California to Panama- 



The cup, probably of this form, has been described and figured by 

 Tuomey and Holmes as an independent species under the name of Hipponyx 

 Bulla, and Conrad has committed a similar " bull " somewhere in his later 

 writings. He referred H. Bullii to the " genus " Cochlolepas Klein. 



This form, which as a living shell is only known from West America, 

 seems to have been one of those which before the elevation of the isthmus 

 spread to the Pacific, and when changes of level or other reasons exterminated 

 the parent stock these distant colonies (as in the case of Cumici) escaped. 



