TORNATKLLIDES OF HAWAIIAN ISLANDS. 215 



Molokai : Western ravine of Karaalo, near the old ditch 

 trail (Cooke & Pilsbry). 



More widely umbilicate than T. procendus, with decidedly 

 more strictly conic spire and a much larger parietal lamella. 

 In the neanic stage there are two small, subequal, columellar 

 lamellae. It is less strictly conic than T. subangulatus. and 

 has a smaller umbilicus. 



Group of T. tha-a nitmi. 



Tornatettides with well-developed columellar i'olds in the 

 adult stage. The shells are ovate-conic in outline ; whorls 

 convex. The columellar folds are parallel, oblique and extend 

 nearly or quite to the margin of the columella. 



This seems to be a natural and easily recognized group. 



Key to the Species. 



a. Shell less than 3 mm. in length, with a faint peripheral 



band ; embryonic whorls faintly spirally striate. 

 b. Broadly conic, the diam. more than half the length. 



T. thaanumi, no. 21. 

 b 1 . Narrowly conic, the diam. about half the length. 



T. diptyx, 110. 23. 



a 1 . Shell more than 3 mm. in length, unicolorous; embryonic 

 whorls not spirally striate. T. idee, no. 22. 



21. T. THAANUMI C. & P., n. sp. PL 47, figs. 1, 2, 4. 



Shell perforate, broadly-ovate, brownish-corneous, with a 

 faint, broad, lighter band at the periphery, dull, quite strongly 

 striate for a Tornatellides, striae minute, very close. Spire 

 broadly conic, apex rounded, quite obtuse. Suture simple, 

 well impressed. Whorls 614, quite convex, increasing very 

 slowly and regularly, the embryonic slightly darker than the 

 rest, the last rotund, subsaccate at the base. Aperture 

 broadly ovate. Parietal lamella low, slightly oblique. Colu- 

 mella of the same color as the shell, straight, narrowly Trian- 

 gular, furnished with .two rather low, oblique folds, both of 

 which extend nearly to the margin of the columella. Peri- 

 stome thin, erect, strongly arcuate. Length 2.75, diam. 1.65, 

 axis of apert. 1.2, parietal lamella 0.13, umbilicus 0.22 mm. 

 broad. 



