180 PROCEEDINGS OF THE ACADEMY OF 
P. solitaria (pl. VIL., fig. 9) has 25—1—25 teeth, with 14 perfect 
laterals. The transition to marginals is very gradual. 
P. Cooperi (pl. VII., fig. 2), 29 —1—29, with 11 perfect laterals. 
P. Hemphilli (pl. VIL., fig. 6) has 20—1—20 teeth, with 7 perfect 
laterals. 
P. Idahoensis (pl. VII., fig. 4) has 33—1—33 teeth, with 14 
perfect laterals. The transition from the laterals to the marginals, 
however, is very gradual. 
P. Haydeni not examined. 
P. alternata (pl. VII., fig. 5). One membrane has 121 rows of 
34--1—-34 teeth, ten of which are perfect laterals. The variety 
mordax, pl. VII., fig. 7, agrees with it in dentition, except the 
number of teeth. I counted 20--1—20, with 5 perfect laterals. 
P. Cumberlandiana (pl. VII., fig. 8) has 24-124 teeth, with 
about 18 perfect laterals. There is an appearance of a side cutting 
point to the third tooth, a decided one beyond the sixth. 
P. tenuistriata, not examined. 
P. perspectiva (pl. VII., fig. 3), 15--l—15 teeth, 7 perfect 
laterals. 
P. striatella (pl. VII., fig. 10), 20-—-1—20 teeth, with 8 perfect 
laterals. Morse gives 16—1—16. 
P. vortex (pl. XX., fig. 4), 18--1—18, with 8 laterals. A marginal — 
tooth is shown in b. 
P. Ingersolli, Bland. The species should, perhaps, be placed 
in Microphysa. Jawof same typeas in H. Lansingg (above), with 
22 ribs. Teeth 16--1—16, with a gradual change from laterals to 
marginals. The latter are low, wide, with one inner, long, blunt 
cutting point, and one outer, small, blunt. The side cusps and 
cutting points of centrals and laterals are well developed. 
P. pauper, Horni, incrustata, not examined. 
P. asteriscus (pl. XVIII., fig. 9). Morse gives 77 rows of 
13—1—-13 teeth ; 6 perfect laterals. I counted 11-—-1—11, with 5 
perfect laterals. The reflected portion of the central teeth is quite 
small. The marginal teeth are like those of Pupa. 
It will be seen that Patula differs from all the preceding genera - 
by the presence of quadrate, not aculeate, marginal teeth, a 
character shared by all the succeeding genera. There does not 
appear any very essential character in the dentition by which to 
distinguish it from many of American sub-genera of Helix, as will 
