NATURAL SCIENCES OF PHILADELPHIA. 253 



p. Prostate. 

 V. d. Yas deferens. 

 p. s. Penis sac. 



r. Retractor muscle of last. 

 or. External orifice of genitalia. 

 g. b. Genital bladder. 

 V. Vagina. 

 Fig. 1. Genitalia of Partula. 

 Fig. 2. " H. Sagemon, Beck. 



Fig. 3. " H. auricoma, Fer. 



Fig. 4. Lingual dentition of Partula amanda, Pease. The last 



figure is the extreme marginal in profile. 

 Fig. 5. Jaw of Partula. 

 Fig. 6. " " Partula gracilis, Pease. 

 Fig. 7. Genitalia of Partula unibilicata, Pease. 

 Fig. 8. " " P. virginea, Pease. 



Fig. 9; " " P. fusca, Pease. 



Fig. 10. " " P. bilineata, Pease. 



Fig. 11. Jaw of P. virginea, Pease. 



Plate XX. 

 Lingual dentition and jaw of: — 



Fig. 1. Nanina subcircula, Mousson. 



Fig. 2, 3. Stenogyra hasta, Pfr. 



Fig. 4. Helix vortex, Pfr. (See p. 180.) 



Fig. 5. Helix septemvolva, Say. (See p. 203.) 



Fig. 6. Cylindrella elegans, Pfr. 



Fig. 7. Succinea Stretchiana, Bland. (See p. 232.) 



Fig. 8. Helix pyrozona, Phil. 



Fig. 9. Macroceramus turricula, Pfr. 



Fig. 10. Holospira Goldfuasi, Pfr. (See p. 183.) 



14. The extreme figure is drawn from another portion of 

 the membrane, where the cusps are more highly de- 

 veloped. 



Fig. 11, 12. Helix astnr, Souv. 



Plate XXI. 



Jaw and lingual dentition of: — • 

 Fig. 1, 2. Helix Arangiana, Poey. 

 Fig. 3. Macrocyclis euspira, Pfr. 



