40 HELIX. 



without chestnut radiations, suture channeled ; whorls 4J, a 

 little convex, rather rapidly increasing, the. last a little deflected 

 in front, base convex. Diam. 3J mill. 



Rarotonga^ Cook's Is. 



H. DECORTICATA, Garrett. PI. 8, figs. 47-50. 



Moderately, deeply umbilicated, thin, subpellucid, ash-colored 

 under a brownish corneous epidermis, decorticated in adults, 

 rarely strigated with chestnut, arcuately costate, the interstices 

 very lightly striated, suture channeled ; whorls 5, convex, 

 slowly increasing, the last deflected above, rounded below, 

 periphery obsoletely angulated. Diam. 4 mill. 



Rvrotonga, Cook's Is. 



H. Otarede, Garrett (fig. 50), is a synonym. It is smaller than 

 H. canalis, umbilicus less open, ribs larger, rougher and more 

 distant; sutural line also less profound, and color different. 



H. HARVEYENSIS, Garrett. PI. 8, figs. 51-53. 



Moderately, deeply umbilicated, thin, subpellucid, greenish 

 ash color, arcuately tessellated with chestnut, densely finely 

 plicate-striate, striae oblique, sinuous, less distinct on the base, 

 suture channeled ; whorls 5, slowly increasing, the last obtusely 

 angulated, deflected above, convex below. Diam. 4-5 mill. 



Rarotonga, Cook's Is. 



In shape and markings it is very closely allied to H. comple- 

 mentaria, a Samoa species, but quite different in the style of 

 sculpture. 



H. YOUNGI, Garrett. PL 8, figs. 54-5(1. 



Widely, perspectively umbilicated, thin, shining, subpellucid, 

 uniform dark brown, closely, obliquely, arcuately, plicately 

 striate, more slightly below, suture channeled ; whorls 4^, 

 convex, rapidly increasing, the last deflected above, convex 

 below. Diam. 4 mill. 



Rarotonga, Cook's Is. 



H. COMPLEMENTARIA, MoilSSOU. PL 8, fig. 57. 



Rather narrowly umbilicated, rugose, striate-costulate, with 

 curved-back radiations of white and grayish corneous, suture 

 subimpressed ; whorls 5, slowly increasing, the last not descend- 



