192 BULLETIN OF THE 



P. Thalia Garr. Mss., in two quarts, was very uniform in size and 

 color. 



P. compacta Pse., in two quarts, was also uniform as to size and color. 

 It is a much larger and heavier shell than P. auriculata Brod., with a 

 heavy flat lip, and, like P. Thalia, it is a well-marked species. 



P. auriculata Brod., in one quart, exhibited the light, unicolored, and 

 banded varieties in about equal numbers. 



P. compacta Pse., P. Thalia Garr. Mss., and P. auriculata Brod., all 

 possess, in a greater or less degree, the "keyhole aperture," which Air. 

 Broderip regarded as especially characterizing P. auriculata. They form 

 a group of very nearly allied species. In P. Garrettii Pse., about one 

 third of the examples exhibited the shell with a brown-colored base. 



A number of depauperated examples were also present in the parcel, 

 beside several hybrids between P. Garrettii Pse. and P. Thalia Garr. 

 Mss. These possessed the brown base of P. Garrettii, with the form 

 and aperture of P. Thalia, but were only half the size. I received a 

 number of the same from Mr. Garrett. 



P. crassilabris Pse. and P. rustica Pse. were each represented by about 

 one quart of specimens. For the most part the former were smaller and 

 more globose than the latter. Both parcels presented numerous de- 

 pauperated examples. When compared in qiiantity, they are seen to 

 merge into each other by easy grades ; only the extremes in form repre- 

 sent the two species of Mr. Pease. They are both terrestrial, and 

 inhabit the same island, their variation being due to station and food 

 plants. Two examples of P. pinguis Garr. Mss. were found in the lot 

 of P. rustica. The former is doubtless only a well-fed specimen of the 

 latter. 



P. lignaria Pse. and P. affinis Pse. were each represented by a 

 quart of examples ; a few of each were banded. The variety P. liijnaria 

 as a rule is a trifle larger and darker in color, and presents more banded 

 examples, than P. affinis. All the adult shells of both varieties (with 

 few exceptions) are dentate, and both exhibit, to a greater or less extent, 

 dark oblique stria) on the body whorl. 



The parcel P. affinis Pse. was labelled " Faarumaia Valley, Tahiti " ; 

 about fifty examples to the quart were banded. Several albinos were 

 present, two of which showed traces of dark bands, and a few pale exam- 

 ples occurred with a bright brown band continued beneath the suture to 

 the apex. One example was found the counterpart of my specimens of 

 P. nitens Pfr. from the Taylor collection, said to be from New HebriHcs ; 

 and three similar banded examples were found in the lot of P. lignaria. 



