PARTULA, SOCIETY ISLANDS. 175 



6. P. MAGDALIN^; Hart/man. PI. 31, figs. 2, 3. 



The shell is rather narrowly umbilicate, globose, with a 

 short, conic spire, thin, fragile; 'white with some corneous 

 streaks under a very thin pale yellowish cuticle, which seems 

 to be usually deciduous above the periphery on the last whorl. 

 Sculpture of minute, close spiral striae much as in P. decus- 

 satula, but weaker above the periphery. Embryonic whorls 

 as in decussatula. Spire very short; whorls somewhat con- 

 vex, the last very much inflated, prominent in the peripheral 

 region, convex beneath Aperture oblique, ovate; peristome 

 reflexed, gray, thin, just noticeably thickened within. 



Length 14.8, diam. 11, aperture 10 mm. 



Length 15, diam. 11, aperture 10 mm., whorls 4 1 /. 



Length 14, diam. 10.3, aperture 9.3 mm., whorls 4*4. 



Marquesas Is. : Santa Magdalina or Fatuhiva Island 

 (Garrett). 



P. magdaliua: HARTMAN, Proc. A. N. S. Phila. 1885, p. 203, 

 fig. in text. GARRETT, Bull. Soc. Malac. France iv, 1887, p. 27. 



This very delicate snail is related to P. decussatula Pfr., but 

 it is very much more inflated, shorter, with a narrower um- 

 bilicus. Of the four examples originally composing the type 

 lot, one has been broken; the example figured by Hartrnan 

 is also damaged by a hole in front (not shown in my figure 

 of this specimen). Perhaps none of the specimens is quite 

 fully mature, but it is evidently a very thin shell at any stage 

 of growth. Figured from cotypes, no. 4263 Carnegie Museum. 



II. SPECIES OF THE SOCIETY ISLANDS. 



The Society Islands are wonderfully rich in Partulas. 

 Both species and individuals are developed in profusion, and 

 differentiation of form and color has been carried further 

 than in any other island group, though there has been no 

 great structural divergence. Probably all of the Society 

 species are referable to two stocks, herein regarded as "sec- 

 tions. ' ' These sections may be defined thus : 

 I. Shell ovate, with short spire, composed of 4 to 4=y 2 whorls, 

 very thin, fragile and subtranslucent ; color pale and 



