222 BULLETIN OF THE 



EXPLANATION OF THE PLATES, 



PLATE I 



Fig. 1, Central tootli of lingual membrane of Mesodon major, the specimen la- 



belled A (see p. 190). 



Fig. 2. Central tooth, two adjoining lateral teeth, and two marginal teeth of lin- 

 gual membrane of Mesodon major, the specimen labelled B (see p. 190). 

 Fig. 3. Same : an outer lateral tooth bearing a side cusp and cutting point (see 



p. 190). 

 Fig. 4. Mesodon Andrewsi : the genitalia. 



ov. oviduct. 



g. b. genital bladder. 



d. g, b. duct of same. 



v. d. vas deferens. 



r. retractor muscle of penis sac. 



p. s. penis sac. 



or. common orifice. 



p. prostate gland. 



Fig, 5. Penis sac of another specimen of same. 

 Fig. 7. Lingual dentition of same, from specimen labelled E. Two central teeth, 



with an adjoining lateral tooth. 

 Fig. 8. Same: marginal teeth. 

 Fig. 9. Same : extreme marginal teeth. 



Fig. 10. Same : first lateral tooth of specimen labelled F (see p. 191). 

 Fig. 11. Same: marginal tooth (see p. 191). 



Fig. 12. Same: specimen labelled M (see p. 191), an outer lateral tooth. 

 Fig. 13. The fourth lateral tooth of Li max flempltilli (see p 205). 

 Fig. 14. Sncr in fa c/iri/sis, Westerlund, copied from the " Vega Expedition," Plate 



III. Fig. 10. 

 Fig. 15. Succinea annexct, Westerlund, copied from the same, Fig. 11. 



PLATE II. 



Lingual dentition of: 

 Fig. 1. Limax maximus. A central tooth with two adjacent laterals; an outer 



lateral ; two marginals, the left hand one the last. 

 Fig. 2. Prophysaon (see p. 216). A central tooth with its adjacent lateral tooth ; 



an outer lateral tooth ; an extreme marginal tooth. 



