THE NAUTILUS. 



cc. Varix, expansion or contraction of the lip rather 

 weak or inconspicuous. 



il. Keeled or angular at the basal periphery, 



rounded or flattened above the keel. 



f. Columella wide and heavy ; alt. 4'6, 



diam. 4'4 ram. P. BUSCHII ' Dkr.' Ffld. 



ee. Columella narrow ; alt. 4'3, diam. 3'2 



mm. P. CONICUS Brot 



<ld. Body whorl squarish, the angles rounded ; 



Columella rather wide; umbilical crescent 



defined by a carina ; lip with a narrow 



varix. Alt. 5. diam. 4 mm. 



P. ORBIGNYI n. sp. 



ddd. A carina at the basal periphery, and two 

 approximate keels on the back above. 



P. TRICOSTATUS Brot. 



dddd. Periphery and base well rounded ; a wide 

 shallow sulcus or two low carina 1 on the 

 back above. Alt. 5'5, diam. 4'8 mm. 



P. LAPIDUM SUPERSULCATl'S II. V. 



aaa. Whorls rounded, without spiral keels, angles or sulci. 



b. Globose or globose-conic ; peristome not nicked or sin- 

 uous. 



c. Not banded ; last whorl rounded ; aperture 

 slightly contracted P. LAPIDUM Orb. 



cc. 3-handed : lip and columella thin. 



P. PETITIANUS Orb. 

 bl>. Ovate, the outer or basal lip sinuous or nicked. 



c. Outer lip expanded or flaring, its face thickened, 

 with two or three nicks or sinuses. Alt. 5, diam. 

 4 - 3 mm. P. SYKESII u. sp. 



cc. Outer lip thin, unexpanded. 



d. Outer lip produced in a broad tongue or 

 lobe, a deep rounded sinus above and 

 below. Alt 5, diam. 4 mm. 



P. BISINUATUS n. sp. 

 dd. Similar, but the upper sinus obsolete. 



P. JilSINUATUS OBSOLETUS n. V. 



ddd. Much more slender ; outer lip retracted at 

 insertion above, sinused at base. Alt. 4'6, 

 diam. o'l mm. P. GRACILIS u. sp. 



