146 PROCEEDINGS OF THE ACADEMY OF 
On CLASSIFICATION. 
The characters of the jaw, combined with those of the lingual: 
membrane, furnish reliable bases of classification. ‘They have 
been considered of various weight by different writers. I here 
propose to treat them as guides only to the greater division of the 
Pulmonata.’ In grouping the various genera it will be necessary 
to include all, both American and foreign to America, in order to 
properly appreciate the value of this grouping. 
Taking, therefore, the whole series of known terrestrial Pulmo- 
nata, the first grand division is based on the presence or absence 
of a jaw. Of the former are the following: Testacella,’ Daude- 
bardia, Streptaxis,' Rhytida, Diplomphalus,® Strebelia 2?" Glan- 
dina, Petenia?? Spiraxis?” Streptostyla," Ravenia?” Strepstos- 
tele,’ Celiaxis 2% Gonospira,” Gibbus? Hnnea.™ 
All the above have aculeate marginal teeth; the lateral teeth 
are always absent; the centrals in some of the genera. 
The following genera have quadrate marginal teeth: Onchi- 
dium, Onchidella,® Peronia,” Buchanania? 
' Tmust not be understood to propose a system of classification. I merely 
place the genera into certain groups, independent of their divisions into 
families. : 
2 Heynemann, Malak. Blatt. X., pl. IL, fig. 5. 
5 Goldfuss verh. Naturh. Vereins der preuss. Rheinl. und Westphalens, 
15th year, 1856, pl. VI., fig. ¢. ce. 
4 Heynemann, Malak. Blatt. XV., pl. IV., fig. 2. 
5 Semper, Nachr. der deut. Malak. Gesellschaft II., 102. 
6 Fischer and Crosse, Journ. de Conch. XXI., 21, pl. IIL., fig. 8. 
7 Jaw and dentition unknown. 8 See this paper. 
® Jaw and dentition not actually known. 
10 Jaw and dentition not actually known ; as restricted, the genus may be 
more correctly placed near Stenogyra. 
1 Fischer and Crosse, Moll. Mex., p. 16, pl. IV., fig. 2. 
2 Jaw and dentition not actually known. 
8 Heynemann, Nachr. mal. Gesel. I. 20, 177, fig. 5. 
14 Jaw and dentition not actually known. 
' Bland and Binney, Amer. Journ. Conch. V. 37, pl. XI. fig. 1, photo- 
graphed. 6 No doubt like the last. 
17 Weynemann, Nach. mal. Gesel. J. 20, 177, pl. XX., figs. 3, 4. 
8 Bland and Binney, Ann. Lyc..N. H. of N. Y. X., p. 340, pl. XVL., 
figs. 3-5. 
19 Heynemann, Malak. Blatt. X., pl. IIL, fig. 13. 
2 Quoy, Voy. de l’Astrolabe, pl. XII. 21 Jaw and lingual unknown. 
