TRACHELIPODA. 79 



mouth dark orange within. Four inches long. Inhabits the 

 Indian seas. 



FAMILY II. COLUMELLARIA. 



Without a canal at the base of the aperture, but having a 

 subdorsal more or less distinct notch, and with folds or plaits 

 on the columella. 



Genus 7— VOLVARIA Lamarck. 



Generic Character Shell cylindrical, convolute ; the 



spire hardly protruding ; aperture narrow, nearly the whole 

 length of the shell ; columella with one or more folds or 

 plaits near its base. 



This genus forms a natural connection betmxt the Columellaria and 

 the Involuta. 



Volvaria cylindr tea. —TnE Cylindric Volvaria. Plate 

 XL fig. 11. Shell cylindrical, white, with one plait on the 

 columella. Half an inch long. Inhabits the British seas. 



This shell, however, is not an apt representative of the genus Vol- 

 varia, it being a Bullina. 



Genus 8 MARGINELLA Lamarck. 



Generic Character. — Shell oblong-ovate, smooth ; spire 

 short, outer lip with an external marginal longitudinal rim 

 or varix; base slightly notched; columella plaited; folds 

 nearly equal. 



The thickening of the outer lip distinguishes these shells from the 

 genera Volvaria and Mitra. There are two sections : 1. with the spire 

 protruded; 2. with the spire not projecting. To the first belongs the 

 following species. 



Marginella ccerulescens. — The Bluish Marginella. 

 Plate XI. fig. 6. Shell bluish- white ; spire short, and acute; 

 lip brownish-purple within; columella with four plaits. One 

 inch long. Inhabits the Indian Ocean. 



Genus 9.— YOLUT A.— Linnceus. 

 Generic Character. — Shell ovate, more or less ventricose; 



