. 
594 
Fig. 10. 
Fig. 15. 
Fig. 25, 
. Germ of m.1, showing specialization of lingually placed dental 
Fig. 27. 
Fig. 33 
34, 
35. 
36. 
ON MAMMALIAN DENTITION. [May 5, 
Figs. 10-14. Gymnura. 
Developing 3rd upper incisor (p7.3) with calcified vestigial milk 
predecessor (di. 3). 
. Germ of 2nd upper premolar (ppm. 2) with reduced milk predecessor 
(dpm. 2). 
. Germ of Znd lower premolar (ppm. 2), milk predecessor (dpm. 2) still 
more reduced. 
. Upper jaw of Gymnura_ showing milk dentition and cavities occupied by 
germs of permanent teeth. 2. 1, first molar ; dpm.2, 2nd deciduous 
premolar. 
. Germ of dpm.3 and ppm. 3, the latter just appearing. 
Piatr XXYV. 
Figs. 15-24. Sorex. 
Developing Ist lower incisor (pz. 1), lingual growth of dental lamina 
(a.l.). 
. Germ of pi. 2 with labial vestigial milk predecessor (di. 2). 
. Ditto, pi.3; ditto, di. 3. Tey 
. Ditto, permanent canine, pe. (i. 4); ditto, de. 
. Plan of enamel germs of upper teeth in relation to the dental lamina 
and to the jaw-bones (pmax. and mz.). 
. Germ of pi. 2 with labial vestigial milk predecessor (di. 2). 
. Ditto of pi. 3 and di. 3 (vestigial). 
22. 
. Ditto of ppm. 4 and dpi. 4 (vestigial). 
. Ditto of ppm. 4 and dpm. 4 (vestigial). 
Ditto of ppm. 3 and dpm. 3 (vestigial). 
Figs, 25-26. Centetes. 
Germ of 7%, 3. 
lamina (d./.). 
Prats XXVI. 
Figs. 27-32. Talpa. 
Horizontal section of the upper jaw, showing the tooth germs in 
relation to the dental lamina; the milk-teeth are well developed, 
while the germs of the permanent teeth are just visible as swellings 
of the dental lamina. 
. Enlarged drawing of a deep horizontal section passing through the 
germs of dc., dpm.1, dpm.2, dpm. 3, and those of their successors 
in the permanent series. pe. very advanced ; ppm.1 transitory, 
never becoming more developed. 
. Clarified jaw of a very young Mole (hairless), showing the milk and 
permanent dentitions @7 sztv. - 
. Frontal section of a specimen about the same age as the last, showing 
dpm. 2 well calcified and the germ of ppm. 2. 
. Difto, ditto, passing through the first premolar (dpm. 1), showing last 
trace of the lingual dental lamina (d./.), 
. Ditto of a young stage, passing through the germ of m.1, showing the 
primitive dentine germ giving rise to the paracone (5), and the first 
trace of the protocone (7), also a very prominent swollen lingual 
development of the dental lamina. 
(a) palatal, (4) external aspect of an upper molar (m.) tooth of Peralestes. 
Ditto, ditto of Centetes (m.1). 
Ditto, ditto of Talpa (m. 2). 
Ditto, ditto of Chrysochloris (m.). 
The numerals attached to the last 4 figures represent an attempt to 
homologize the cusps. 
