194 TtRRlTELLlDiE, 



Subgenus Arcotia, Stoliczka, 1868. 



Turreted, elongated, spirally' striate, the incremental lines 

 straight, not curved ; columella excavated, aperture angulately 

 rounded, subefFuse anteriorly. 



Jurassic and Cretaceous of India. T. Indica, Stol. (S. and S. 

 Conch., t. 67, f. 64). 



Subgenus Lithotrochus, Conrad. 



Shell having the appearance of an elongated Trochus ; spire 

 obtuse, the whorls numerous, transversely grooved, last whorl 

 carinated, smaller than the spire ; there is a thickened sutural 

 band, with very numerous growth-strise ; aperture subtetragonal, 

 entire. 



Lias of Chili. T. Humboldtii, Buch (S. and S. Conch, t. OT, 

 f. 66). 



Genus PROTOMA, Baird, 1870. 



Shell turreted, with flattened whorls, aperture oval, narrowly 

 channeled and excised in front, with a basal swelling and a 

 fasciole around the excision, lip sinuous behind. Operculum 

 circular, corneous, multispiral. 



A single recent species is known, from West Africa. 



This is the genus Proto, of authors, not Defrance, represented 

 in the Miocene of Europe. 



? Genus GLAUCONIA, Geibel, 1852. 



Shell turriculated, conical, sometimes pupiform, the whorls 

 less numerous than in Turritella, and crossed by costulations ; 

 outer lip notched or sinuated by an imj^ressed furrow which 

 winds round the last whorl ; aperture rounded, continuous ; colu- 

 mella usually distinctly umbilicated. There are about 30 creta- 

 ceous species, Europe^ India and America. Omphalia, Zekeli, 

 1852 (not Omphalius, Phil.), and Cassiope, Coquand, 1866, are 

 synonyms. 



Usually considered a member of this famih', but is remarkably 

 allied to Melanatria. 



