204 PROCEEDINGS OF THE CALIFORNIA 



oblong, sub-quadrate, anterior outline slightly concave, convex posteriorly ant$ 

 the sides flattened ; base crenulate ; interior radiately grooved. 



Length, sixteen ; height, eight ; diameter, twelve mill. 



Habitat, Samoa and Viti Islands. 



A rare species, remarkable for the elegance of its sculpturing.. 



FlSSURELLA FKNESTRATA, Grt. 



Shell depressly conical, ovate, ashy-white, rarely rayed with slate, radiatelj"- 

 ribbed; eleven or twelve of the ribs large, rounded, increasing in size posteri- 

 orly, with small ones interposed, all crossed by thin concentric ridges, which 

 form vaulted scales on the posterior ribs ; interstices finely clathrate ; fissure a 

 little anterior, oblong, sub-quadrate, slightly contracted anteriorly ; base irre- 

 gularly crenulate ; interior radiately grooved. 



Length, fifteen ; height, seven ; diam. twelve mill. 



Habitat, Viti and Samoa Islands. 



A very rare species. It can be readily distinguished by its three large- 

 posterior ribs being much more developed than the others. 



Genus Pitys, Beck. 



PiTYS MAUPIENSIS, Grt. 



Shell umbilicate,. sub-discoid, thin, sub-pellucid, elcvately striated, stri;c- 

 crowded, finer beneath, brownish, more or less tessellated with dark brown, 

 and sometimes the body adorned with zigzag stripes; spire convex, ai)ex Hat :. 

 suture rather deeply impressed ; whorls six and a half, rounded, regularly and, 

 slowly increasing, the last one slanting inward from the shoulder; umliilicns 

 small, deep, about one-fifth the greatest diameter of the shell ; aperture vertical, 

 narrow, luniform, fauces with four, columella with one, and the parietal regioiii 

 with throe lamelloe ; peristome thin, simple. 



Diam., three ; height, one and a half mill.. 



Habitat, Maupiti Island, Society Islands. 



A common species, peculiar to the above location, where it occurs under 

 dead wood and among stones. It belongs to the same group as Pihjs mmliceHa,. 

 Fer. and P. muliilamenata, Grt. 



Pitys TANEiE, Grt. 



Shell umbilicate, discoid, thin, sub-pellucid, brownish liorn color, tessellated' 

 and rayed with deep brown ; plicately ribbed, riijs small, oblique, acntciy 

 curved, somewhat irregularly disposed, rather distant, but finer and more- 

 crowded beneath ; spire convex, flattened at the apex ; whorls six and a half,, 

 convex, slowly and regularly increasing, slightly sulcate near the suture, last 

 one acutely carinate, flattened above, not descending in front, convex beneath, 

 and angular near the umbilicus ; suture well impressed ; umbilicus large, per- 

 spective, freely showing the whorls, a little more than a third the greatest 

 diameter of the shell ; aperture oblique, rhomboid-lunate, wider than deep ;. 

 parietal region with a small revolving lamella; peristome thin, simple. 



Diam., four and a half; height, one and a half mill? 



Habitat, Maupiti Island, Society Islands. 



A very abundant species, found on the ground in damp forests. It belongs- 

 to the group rei)rescnted by P.fninifncta, field and IJunliincnsui. 



