60 DAVENPORT ACADEMY OF NATURAL SCIENCES. 



ferent. My extensive suit of these shells from Tortugas does not show 

 any distinction even as a variety, as the variation is from the most slen- 

 der forms to those almost pupoidal, and with every shade of color from 

 dark brown, through various patterns of painting, to pure white. Some 

 of these shells are not over 6 mm. in length. C. eriense Val. is a syn- 

 onym of ferrugineum. 



Cerithium muscarum Say. A most beautiful and abundant form in 

 Florida. A small, very delicate variety, with chestnut-colored puncta- 

 tions, is found on the Keys; and I also have it from the Bermudas and 

 Honduras, but it connects with the type. 



Cerithium guiniacum Phil. ? A broken and slightly worn shell was 

 picked up at the Tortugas which agrees well with this species, and is 

 certainly like nothing else that I have seen. I have another worn speci- 

 men of the same from Utilla, Honduras. 



Bittium varium Pfr. Abundant from New York to Florida, and 

 varying from a dirty white to chocolate, with light colored varices. 



Cerithiopsis tuberculdris Mont. Tortugas. A single fresh shell, the 

 var. acicula Brus., perhaps, having a broad whitish band above the 

 suture. 



Cerithiopsis greenii C. B. Ad. Tortugas. 



Cerithiopsis pun ctat urn L. Tortugas; Tampa Bay. Better known as 

 C emersoni C. B. Ad. 



Cerithiopsis flavum C. B. Ad. Two slightly worn shells were found 

 at the Tortugas. 



Cerithiopsis pule Jicllum C. B. Ad. Tortugas. 



Cerithiopsis kobelti Dall. Tortugas. 



Seila terebrale C. B. Ad. Common on the West coast and Keys ; 

 Cedar Keys, from Mr. Hinkley. 



Potamides scalariformis Say. Abundant throughout the West coast 

 and Keys. 



Potamides iostoma Pfr. Tampa and Sarasota Bays. Narrower than 

 P. scalariformis, and at once distinguished by having varices. 



Potamides tenuis Pfr. Tampa and Sarasota Bays. 



Potamides costata Da Costa. One shell was found in Tampa Bay. 



Potamides turrita Stearns. Shaw's point; three shells. Occasion- 

 ally found elsewhere. Shells received from Cedar Keys, from Mr. 

 Hinkley, and labeled P. tenuis Pfr. by Mr. Dall, I think are the same 

 as this. 



Pyrazus minimus Cm. One of the most abundant and variable 

 shells of the west coast of Florida. Specimens vary from ashy white 

 to almost jet black, and are often chestnut, chocolate, or even reddish. 

 Many are beautifully variegated with spiral bands of white, chocolate, 

 brown, and yellowish. The best distinguishing character is the slightly 

 pinched up nodulous plications on the upper part of the whorls, but 

 they are not always so marked, as I have specimens which are nearly 

 smooth. It is Lampanella scptemstriata Say., L. nigrescens Menke, 



