THE NAUTILUS. 



89 



tween the umbilical area and the stronger thread into three equal 

 parts. Aperture very broadly oval, posterior angle very obtuse; 

 outer lip thin, showing the external sculpture within; columella very 

 slender, slightly twisted and very slightly revolute, provided with a 

 very weak fold, wliich is scarcely discernible in the aperture, but 

 becomes apparent when the pillar is exposed by grinding ; parietal 

 wall glazed with a light callus. 



Specimens were found in the Danvers River, on a mud flat be- 

 tween tides, most of which are in the Winkley collection, and seven 

 in the U. S. National Museum, cat. No. 208U67. The one figured 

 has 5i whorls and measures, length 2.15 mm., diameter 0.8 mm. 



NEW HELICINA AND STROBILOPS FROM FLORIDA. 



BY H. A. PILSBRY. 



Several years ago Mr. G. H. Clapp called my attention to a form 

 of Helicina differing in several respects from H. orhiculata Say, the 

 specimens having been received from Mr. C. T. Simpson, who col- 

 lected them at Lemon City, Florida. At about the same time Mr. 

 Vanatta encountered the form in material from Lee Co., Fla., col- 

 lected by Mr. C. B. Moore. He subsequently published a list of 

 these shells (Nautilus for January, 1908, pp. 99-104), mentioning 

 the form in question as Helicina orhiculata var. clappi Pils. MSS. 

 No description has been published. 



Helicina orhiculata was described from the mouth of the St. 

 John's River. The types, four specimens, are still preserved with 

 Say's label. They are globose, very pale greenish-white, and meas- 

 ure from alt. 6, diam. 6.8 mm., to alt. 6.3, diam. 7.7 mm. There is 

 a distinct tooth at the junction of the columellar and basal lips. The 

 periphery is well rounded. 



In the St. John's River valley, away from the coast, and where 

 calcareous material is almost wanting in the soil, there is a small 

 race of orhiculata, measuring, alt. 5.5, diam. 6.8 mm., to alt. 4.5, 

 diam. 5.1 mm. 



H. orhiculata extends from Florida and Georgia west to Tennessee 

 and western Louisiana. West and southwest of this it is entirely 

 replaced by H. orhiculata tropica ' Jan.' Pfr., distinguished by its 

 heavier shell and very thick lip. 



