TORNATELLINA. 169 



widely, the present species having no distinct columellar la- 

 mellae and no palatal serrate plate, though there is a low pala- 

 tal callus. It is not a typical Lamellina, but the palatal cal- 

 losity removes it from Tornatellinops. 



The basal callus passes out from behind the columellar 

 callus in a rather peculiar way in this species and T. micros- 

 toma. 



Section TORNATELLINOPS, n. sect. 



Lamellidea PILS., 1910, definition, but not the type assigned. 



Tornatellinte with the columella twisted and somewhat cal- 

 loused, forming an oblique fold above, but not bearing a colu- 

 mellar lamella at any stage of growth; there are no ribs, 

 plicaB or denticles within the outer lip at any stage. Shell 

 imperforate, oblong-conic, composed of 5 to 6 whorls. Type 

 T. novoseela-nd/ica. 



Some species of Lamellina, in the adult stage, are indistin- 

 guishable from this group, but their young stages differ. 

 Most of the species now placed in Tornatellinops are known 

 only by the adult stage, and their systematic place is there- 

 fore more or less uncertain. Some of them are likely to turn 

 out to belong to other sections, when series of the young are 

 examined. Elasmatina differs from this group by its long 

 contour and numerous whorls. 



This group, under the name Lamellidea, was properly de- 

 fined in the synopsis published by the senior author in 1910 ; 

 but unfortunately the species then selected as type does not 

 agree with the definition, proving to have palatal ribs in the 

 neanic stage. 



25. T. MONODONTA Pilsbry & Hirase. PL 37, figs. 1, 2. 



Shell imperforate, ovate-conic, thin, pale yellowish-corneous, 

 imperfectly transparent, almost smooth. Spire straightly 

 conic, the apex obtuse. Whorls 4%, moderately convex, the 

 last somewhat swollen. Aperture oblique, ovate, somewhat 

 less than half the total length. Outer lip thin and simple, 

 columella strongly twisted, forming a white spiral fold. No 

 parietal lamella. Length 3.25, diam. 1.9 mm. 



