160 TORNATELLINA. 



mella is triplicate, the upper fold moderate, the median very 

 strong, and the lower forming a minute nodule. There are 

 two strong, tridentate palatal ribs visible in the aperture. 

 Part of this armature does not show in the direct front view 

 figured. One of Ancey's types of T. extincta (all of which 

 are at the metaneanic stage) is 2.1 mm. long, with 4% whorls. 

 It agrees exactly with young of grocilis. 



The most distinctive characters of adult specimens of T. 

 gracilis are: the cylindrical shell (the last whorl being 

 scarcely broader than the penultimate ) , the broad shallow de- 

 pression of the last whorl and the rather small aperture. The 

 examples from Round Top, Oahu, one of which is figured 

 (fig. 7), differ slightly from the shells from the other locali- 

 ties. Adult shells are shorter and broader in proportion to 

 their length and the parietal lamella is not as strongly de- 

 veloped. 



Specimens of this species from Laysan Island, collected by 

 Professor Win. A. Bryan, are scarcely separable from typical 

 Hawaiian material. They differ only in having a slightly 

 smaller shell and in being a shade lighter in color. 



The original account of T. extincta follows : Shell elongate, 

 oblong, imperforate, corneous, fragile, smooth, glossy. Spire 

 long-conoid, a little obtuse. Whorls 5, convex, regularly in- 

 creasing, suture minute, margined by transparence; last 

 whorl ovate, convex. Aperture suboblique, armed with a 

 large and strong parietal lamella, an acute, oblique, twisted 

 columellar fold, and a vertical lamina more or less visible in 

 the throat. Length 2.25, diam. 1, alt. aperture .75 mm. Cen- 

 tral isthmus of Maui, the types from earth washed out of sub- 

 fossil specimens of Amastra extincta Pfr. (Ancey). 



'Easy to recognize among Hawaiian forms by the absence 

 of a perforation, its palatal plicae and the simple columellar 

 fold" (Ancey). 



20. T. OBLONGA Pease. PI. 41, figs. 6, 9 ; pi. 42, figs. 7 to 10. 



For description and synonymy of oblonga see page 162 under 

 Polynesian species. 



Kauai : Lihue, Kipu, Haena, Wainiha and Kilohana 



