GUDE : SPECIES OF PLECTOPYLIS. 



35 



It differs from rieetopylis minor in being larger and more elevated, 

 and having a wider and deeper umbilicus. The parietal armature 

 differs in having an additional fold above the vertical plate, and the 

 anterior denticles are almost united to this fold. The palatal 

 armature differs in the posterior folds being very short and almost 

 reduced to denticles. Figs. 1 1 a-c show the shell in three different 

 aspects. Fig. ii d gives the posterior view of the two armatures ; e, 

 the inside of the outer wall ; and /, a portion of the parietal wall, 

 with its plate and folds. All the figures are enlarged. — (" Science 

 Gossip," iv, p. 264.) 



Plectopylis trochospira var. boholensis, Gude, 



differs from the type in being smaller and having a narrower umbilicus. 

 Major diameter, 3*25 mm.; minor diameter, 3 mm.; altitude, 175 

 mm. 



Hah. — Bohol Island, Philippine Islands. Type in Mr. Ponsonby's 

 collection. 



Two specimens kindly lent to me by Mr. Ponsonby, labelled with 



dgfc^ the manuscript name, " Pleciopylis frochosjnra var. bolioleiisis 



^^ (Mollendorff)," certainly represent a distinct variety. They 



•"^ are smaller than the type, and the umbilicus is narrower. The 



Fig. 12. — Plectopylis trochospira var. boholensis, Gude. 



armature is nearly identical, but the palatal folds are connected at 

 their posterior terminations by a very slight transverse sinuous ridge, 

 plainly discernible externally through the shell-wall. — (Ibid., p. 285.) 



Plectopylis achatina var. obesa, Gude. 



Differs from the type in being more compressed and higher in propor- 

 tion to the diameter ; in the last whorl not widening suddenly at the 

 aperture, and in the lower side sloping from the periphery to the 

 umbilical angulation ; the right margin of the peristome is depressed ; 



Fig. 13. — Plecto'pijlis achatina var. obesa, Gude. 



