NATURAL SCIENCES OF PHILADELPHIA. 251 
Helix crispata, Pfr. (Hurycratera.) Am. Journ. Conch., VII. 179. 
Helix orbiculata, Fér. (Dentellaria.) Am. Journ. Conch., VI. 205, 
pl. ix. fig. 14. Jaw apparently costate. 
Helix Isabella, Pfr. (Dentellaria.) Am. Journ. Conch., VII. 179. 
Jaw surely costate. 
Helix dentiens, Fér. (Dentellaria.) Am. Journ. Conch., VII. 179. 
Jaw as in last. 
Helix perplexa, Fér. (Dentellaria.) Ann. Lyc. N. H. of N. Y., X. 221. 
Jaw with traces of anterior ribs, but with a median projection to its cut- 
ting edge. k 
Helix Schroeteriana, Pfr. (Pleurodonta.) Am. Journ. Conch., VII. 
179. 
Lingual membrane alone examined. 
Helix acuta, Lam. (Pleurodonta.) Am. Journ. Conch., VI. 204. 
Helix excellens, Pfr. (Caracolus. ) Am. Journ. Conch., VII. 180. 
Lingual membrane only examined. 
Helix Bermudensis, Pfr. (Caracolus.) Ann. Lyc. N. H. of N. Y., X. 
221. 
The species shown to belong to the Vitrinine. 
Helix fuscocincta, Ad. (JLeptoloma.) Am. Journ. Conch., VII. 180. 
Jaw unlike generic description in having a median projection and no ribs. 
Helix Phcenix, Pfr. (Acavus.) Am. Journ. Conch., VII. 180. 
Jaw with no anterior ribs. 
(c.) With jaw in separate pieces. 
Liguus virgineus, Lin. Am. Journ. Conch., VI. 209, fig. 3, 4, lingual 
membrane. 
Liguus fasciatus, Mill. Am. Journ. Conch., VI. 211, pl. ix. fig. 6. 
Orthalicus zebra, Mull. Am. Journ. Conch., VI. 212, pl. ix. fig. 2. 
Orthalicus undatus, Brug. Am. Journ. Conch., VI. 218, pl. ix. fig. 10, 
12. 
(d.) With jaw with supplementary upper plate. 
Succinea effusa, Shuttl, Am. Journ. Conch., VI. 213, pl. ix. fig. 15.. 
Succinea Nuttalliana, Lea. Ann. Lyc. N. H. of N. Y., IX. 282, fig. 1. 
PULMONATA LIMNOPHILA. 
Limneea appressa, Say. Am. Journ. Conch., VII. 161, pl. xii. fig. 1, 2, 5. 
Limnza megasoma, Say. Am. Journ. Conch., VII. 162, pl. xii. fig. 3, 6. 
Pompholy=x effusa, Lea. Ann. Lyc. N. H. of N. Y., IX. 290, fig. 9.— 
Amer. Journ. Conch. VI. 312, pl. xviii. 
Planorbis trivolvis, Say. Ann. Lyc. N. H. of N. Y., IX. 292, fig. 10. 
Melampus bidentatus, Say. Ann. Lyc. N. H. of N. Y., 1X. 286, fig. 7. 
