66 GARRETT: ON POLYNESIAN MITRID^. 



A common vSociety Island species found buried in sand 

 in shallow water inside the reefs, and not under stones as 

 stated by Reeve. It is very rarely found at the Pammotu 

 and Viti groups, and has been recorded from the Pelew and 

 Caroline Islands. 



The three Viti examples which I obtained are much 

 smaller and more slender than Eastern shells, and are nearly 

 a uniform white color. Mr. Reeve's figure is colored pale 

 bluish-green, though he very correctly describes the ground 

 color as whitish. The transverse lines are brownish or jet- 

 black. The columella is eight-plaited — not nine-plaited as 

 stated by Mr. Reeve. 



Genus IMBRICARIA Schumacher. 

 i6i. Imbricaria Olivaeformis Swainson. Reeve, 1. c, pi. 



XXvii., fig. 212. 



We found this species inhabiting all the groups except 

 the Marquesas, Cook's and Tonga Islands. It appears to 

 be rather scarce everywhere except the Society Islands, 

 where it is very abundant and gregarious in sand inside the 

 reefs. 



It appears to be an aberrant form intermediate between 

 Cylindra and hnbricaria, and might with equal propriety be 

 referred to either genus, though it is usually placed in the 

 latter. Mr. Swainson considered it to be a Mitrella ( = Swain- 

 sonia), the type of which is Afitra fasciata. It attains a 

 larger size than represented by Reeve's figure. The color is 

 ivory-white, under a very delicate luteous epidermis. The 

 punctured spiral lines are confined to the upper portion of 

 the shell. 



The animal is creamy-white, with a cream-yellow creep- 

 ing disk. 



