84 Enamel in the Teeth of an Embryo Edentate 



Rose, C, 93. — Ueber die Zahnentwickelnng der Kreuzotter (Vipera berus 



L.). Anat. Anzeiger, Bd. IX, p. 448. 

 SuDDUTH, W. X., 86. — American System of Dentistry, j)p. 640-645. Lea Tiros., 



Phila. 

 Tomes, C. S., 74, — On the Existence of an Enamel Organ in the Armadillo. 



Quarterly Journ. of Microsc. So. 1874, p. 48. 

 Thomas, O., 89. — A Milk Dentition in Orycteropus. Proceed. Eoy. Soc, 



Vol. XL VII, 1889-90, p. 246. 

 Weber, Max., gi. — Beitrage zur Anatomie und Entwickelung des Genus 



Manis. Zoologische Ergebnisse einer Reise in Niederlandisch- 



Ostindien, Bd. II, 1891. 



EXPLANATION OF PLATES I AND II. 

 EEFEEENCE LETTERS. 

 c, cartilage. iep., inner laj^er of enamel organ. 



ct., connective tissue. mm., mucous membrane. 



ce., columnar cells over thinner oep., outer laj^er of enamel organ. 



portion of enamel layer. 0., odontoblast cells. 



d., dentine. sr., stellate reticulum. 



dp., dental papilla. si., stratum intermedium. 



e., enamel. sb., secondary bud. 



CO., enamel organ. stb., portion of second tooth-bud. 



er., epithelial ring. nd., uncalcified dentine. 



eb., epithelial band. *., space left by shrinkage 



fep., flattened cells of enamel of specimens. 



organ. 

 All figures (except Plate I) were made with the aid of the Camera 

 Lucida and in the process of reproduction were reduced about one-third. 



PLATE I. 



Photograph of embryos Dasypus novemoincttis L., showing placentation. 

 Reduced about one-third. 



PLATE II. 



Fig. 1. Longitudinal section, lower jaw 8.5 cm. embryo, showing rudi- 

 mentary incisors. Leitz obj. 3, Oc. 1. 



Fig. 2. Rudimentary incisor of Fig. 1 enlarged, showing enamel sepa- 

 rated from the dentine and fractured in the direction of the enamel rods. 

 Leitz obj. 7, Oc. 1. 



Fig. 3. Longitudinal section, lower jaw 9 cm. embryo, showing enamel 

 in the first back tooth. Leitz obj. 3, Oc. 1. 



Fig. 4. Enamel and dentine of Fig. 3 enlarged, showing uncalcified 

 dentine and odontoblast cells. Leitz obj. 7, Oc. 1. 



Fig. 5. Longitudinal section, lower jaw 8.5 cm. embryo. A portion of the 

 tooth-bud of the fifth back tooth, showing the secondary bud conaing from 

 the outer epithelial layer of the enamel organ. Note Tomes' processes of 

 the inner epithelial layer directed toward the dentine. Leitz obj. 3, Oc. 4, 

 tube drawn out to 20 cm. 



Fig. 6. Longitudinal section, lower jaw 8.5 cm. embryo, showing the 

 enamel organ of the eighth tooth-bud still connected by an epithelial band 

 to the enamel organ of the seventh tooth-bud. Leitz obj. 3, Oc. 1. 



