MANUAL OF CONCHOLOGY. 



Family OLEACINID./E. 



Most systematic writers on land snails, including Pfeiffer 

 (Nomenclato'n Heliceorum Viventium, 1878), have placed 

 Spiraxis, Melaniella and the slender species of Varicella 

 among or adjacent to the Stenogyroid Achatinidcc. Their 

 true position proves to 'be in the family Olcacinidtr, which 

 was monographed by Mr. Tryon in Vol. I of this series. 

 Since species of these groups will naturally be looked for 

 among the Stenogyroid groups, it has 'been thought best to 

 insert them here. The opportunity has been taken to revise 

 the 'classification of the Oleacinidcs and to supplement the 

 account in Vol. I by illustrations and descriptions of new 

 forms and of others published since the appearance of that 

 volume, without duplicating matter contained therein. 



Genus PSEUDOSUBULINA Strebel. 



Pseudosubidina STREBEL, Beitrag Mex. Land und Siisswasser 

 Conchyl. v, p. 117 (1882). v. MARTENS, Biologia Centrali 

 Americana, Mollusca, p. 301. TRYON, Manual of Conchology, 

 2d. Series, i, p. 50. 



The shell is slender and turrite, pale and subtransparent, 

 closely resembling that of Subulina; but with fine rib-sculp- 

 ture. Columella usually more or less distinctly truncate at 

 the base. Apical whorl smooth. 



The jaw is represented by a slight crescentic thickening of 

 the epithelium, distinct on its lower border, but passing in- 

 sensibly into the general integument at the sides and above. 

 It is composed of narrow plates. 



The radula is Oleacinoid, the teeth arranged in V-shaped 

 rows. Central tooth rudimentary, with a small cusp. The 



