04 HELIX. 



with five subequidistant lamellae within the margin, besides two 

 on the columella and four on the parietal wall. 



Diam. 3'5 mill. 



Rarotonga, Cook's Islands. 



H. ZEBRINA, Garrett. PI. 12, figs. 17-19. 



Narrowly umbilicated, thin, pellucid, shining, whitish cor- 

 neous, with chestnut tessellations on the spire and flexuous 

 stripes on the body-whorl ; whorls 5^, convex, slowly increasing, 

 membranously closely ribbed, the interstices under the lens 

 elevately striated, suture deeply impressed, aperture with three 

 lamellae within the lip and two on the parietal region. 



Diam. 4 mill. 



Rarotonga, Cook's Is. 

 H. RAROTONGENSIS, Pease. 



Umbilicated, rather thin, radiately elevately striate, suture 

 well impressed ; whorls 5, convex ; aperture with three parietal 

 and two basal lamellae ; yellowish, tessellately strigated with 



chestnut. Diam. 3 mill. 



Rarotonga, Cook's Is. 

 Un figured. 



H. PARVIDENS, Pease. PI. 12, figs. 20-22. 



Rather widely deeply umbilicated, with small, close, elevated 

 striae, yellowish, tessellated with chestnut ; whorls 5, a little 

 convex above, more rounded below, suture well impressed ; 

 aperture with two lamellae in the throat, one on the columella, 



and three on the parietal wall. 



Tahiti. 

 H. incerta, Mousson,is a synonym. 



H. D^DALEA, Gould. PI. 12, figs. 23-25. 



Yellowish brown, tessellated with chestnut, with acute, close, 

 scabrous costuhitions ; whorls 6, narrow, rounded below, suture 

 impressed; aperture with nine lamellae, of which four are on 

 the parietal wall, one on the columella, two at the base and 



three within the lip. Diam. 2'5 mill. 



Ins. Tahiti, Matea. 

 H. suBDyEDALEA, Mousson. PL 12, fig. 26. 



Widely umbilicated, unequally costulate-striate, light cor- 

 neous, sometimes with oblique chestnut stripes, suture deep; 

 whorls 5^, slowl} T increasing, narrow, the last a little tumid 



