28 



Observations on the Terrestrial 



locality where they were numerous, I counted eighty-three speci- 

 mens on a single small leaf. Dense hard wood growths appear 

 to be their favorite position. They prefer the rotten bark of 

 beech trees, and frequently are found in the large forms of fungi, 

 such as Polyporus and Boletus. The periostraca is raised in 

 coarse ridges running parallel with the incremental striae ; these 

 ridges become more prominent as they approach the umbilical 

 region ; they frequently coalesce at, or near the suture ; the faint- 

 est perceptible revolving lines are also present, which become 

 more prominent near the umbilicus, and seem to be arranged in 

 pairs. {Flate 2, Fig. 1.) 



The buccal plate, (Fig. 70J is 

 made up of sixteen long slender 

 corneous laminae, recurved at their 

 cutting edges, these plates partially 

 Fig. 70. lapping over each other. 



Palatal membrane, 54-13-1-13. Plates long and narrow, becoming narrower 

 as they aj^proach the sides of the membrane. Plates transparent, denticles 

 light horn color, central plate largest with one small rounded denticle, laterals 

 with two equally short rounded denticles, those on the verge of the membrane 

 having three minute denticles, laterals and uncini not distinguishable. (PL 8, 

 Fig. 71.) 



This species described by Lea over twenty years ago, has until 

 recently eluded detection ; it has an extended distribution in this 

 country, having been found in Ohio, New York, Massachusetts, 

 and in nearly every portion of Maine. It is very common in the 

 vicinity of Cambridge, Mass. Its extreme minuteness has proba- 

 bly oftentimes caused it to be overlooked. The 

 similarity between this species and pygraaea 

 '^'''"'\r 1) of Europe is very close, and it seems singular 

 Fi(j. G9. that it has never been referred to that species. 



Figure 69 represents a specimen of Punctum minutissimum from 

 Bethel, Maine, and figure 72 a specimen of P. 

 pygmaea, from Florence, Italy. Our shell 

 never attains the size of P. pygmroa and the 

 suture is nearer the centre of the body whorl. 

 The spire is more elevated and the whorls re- 

 volve more closely in our shell. The two shells highly magnified 

 exhibit faint revolving lines, which in P. pygmaea are more dis- 



