70 HELIX. 



the edge often cut by the costulae so as to be fimbriated, base flatly 

 convex, nearly smooth, whitish, a little mottled with chestnut round 

 the outer portion ; aperture with one or two parietal lamellae. 



Tahiti (Jacq.), Sandwich Is. (Pease). 



A very distinct species, erroneously referred by Garrett to the 

 synonymy of H. coarctata. I have before me two trays of shells 

 named H. laminata, Pease, from the " Sandwich Is.," one of them 

 from the describer, which undoubtedly represent the same species. 



H. FRATERCULA, Pease. PI. 13, figs. 64-66. 



Somewhat solid, yellowish, umbilicated, with scarcely oblique, 

 close, rugose costulations ; whorls 7, excavated in the middle, the 

 last with acutely carinated periphery, base plano-convex, closely, 

 finely radiately costulate ; umbilicus cavernous, constricted above ; 

 lip with two (sometimes three), columella with one, parietal wall with 

 one or two revolving lamellae. Diam. 6 mill. 



Rarotonga. 



Described as H. sculptilis, Pease, preoccupied by Bland. 



H. SUBCAVERNULA, Tryon. PL 13, figs. 67-69. 



Umbilicated, somewhat solid, ashy or brownish corneous, here 

 and there darker brown, often tessellated with brown above, 

 obscurely radiated below ; whorls 7, convex, the last acutely 

 carinated, closely obliquely costulate, the interstices minutely 

 striate ; umbilicus deeply cavernous with contracted margin ; aper- 

 ture with two, rarely three remote lamellae in the throat and two on 

 the parietal .region, columella uniplicate, sinuate. Diam. 6 mill. 



JRarotonga, Cook's Is. 



Described by Garrett as H. cavernula, preoccupied by Hombr. et 

 Jacq. 



H. TUMULOIDES, Garrett. PL 13, figs. 70, 71. 



Rather thick, whitish to yellowish corneous, tessellated with chestnut 

 above, radiately strigate below ; whorls 7, plano-convex, the last angu- 

 lated, periphery acutely carinated, obliquely striate, the striae more 

 distant and plicate in the upper whorls, suture linear, subcarinately 

 margined, base plano-convex ; umbilicus cavernous, constricted ; 

 aperture with two median approximate lamellae in the throat, 

 columella with a single plication, parietal region with a median 

 lamella. Diam. 7 mill. 



JRarotonga, Cook's Is. 



