248 TORNATELLIDES OF HAWAIIAN ISLANDS. 



Parietal lamella low, serrate, in front the space between the 

 serrations is partly filled, in back the spine-like serrations are 

 free, about one-third the height of the lamella. Columella 

 broadly triangular, furnished with two low, almost transverse 

 and nearly equal folds, the lower of which extends to the mar- 

 gin of the eolumella. Umbilicus rather large, perspective, 

 about one-fifth the diameter of the shell. Peristome thin, 

 erect. Length 2.6, diam. 1.5, axis of apert. 0.85, par. lam. 

 0.12, umb. 0.33 mm. 



West Maui: Waikapu (Forbes). Type no. 36239 Bishop 

 Museum. 



In an immature specimen with 5 whorls the lower columellar 

 fold is large and transverse, arid is much stronger than the 

 upper. The latter is indicated by a low raised line and is re- 

 markably weak for such a young shell. The serrations of the 

 parietal lamella are more distinct than in the adult specimens. 

 The embryonic whorls are smooth (fig. 8). 



This is an extremely rare shell, of which only four speci- 

 mens were found by Mr. Forbes, two adult and two immature. 

 The convex outlines of the spire easily separate it from all 

 other species of this group. 



520. T. FORBESI NANUS C. & P., n. subsp. PI. 52, figs. 5, 10. 



The shell is smaller than the typical form, thin, glossy, 

 transparent. The aperture is rather large. The parietal la- 

 mella is low, cut nearly to its base by the elongate, spine-like 

 serrations. The columella is broadly tumid, furnished with 

 two equal low thread-like folds, both of which extend to the 

 margin of the columella. The umbilicus is large, perspective, 

 about one-fourth the diameter of the shell. Length 2.4, diam. 

 1.5, axis of apert. 0.92, par. lam. 0.11, umb. 0.38 mm. 



Hawaii: Hilo; Reed's Island (Cooke) (type locality), 

 Rainbow Falls (Thaanum, Cooke); Kukaehaele (Thaanum), 

 Puna (Spalding), four miles Olaa (Cooke). Type no. 36240 

 Bishop Museum, cotypes no. 111720 P. A. N. S., and Thaa- 

 num 's coll. 



This variety seems to be widely distributed over the island 

 of Hawaii, but is extremely rare. The specimens from Reed's 



