J 



APR 6 1901 



DEVELOPMENT OF TEETH IN HATTEEIA PUNCTATA. 161 



The Development and Succession of Teeth in 

 Hatteria punctata. 



By 



H. I§peiicei' Ilai'rii^oii, B.l^c.(L.oii«l.)f A.R.C.Sc, 



Demonstrator and Assistant Lecturer in Biology, University College, Cardiff. 

 (Prom the Zoological Laboratory, Royal College of Science, London, 

 and University College, Cardiff.) 



With Plates 10—12. 



Introduction. 



The dentition of Hatteria present.s certain j)eculiur and 

 characteristic features, wliicli have always attracted atten- 

 tion, and many of which have not 3'et received adequate ex- 

 planation. I need only mention here such points as the 

 structure of the premaxillury and anterior mandibular teeth, 

 the irregularity in occurrence and number of vomerine teeth, 

 and the part taken by the edges of the jaws when the teeth 

 have become worn down. Other matters on which uncer- 

 tainty exists are the presence or absence of enamel, and the 

 extent of the tooth change, which is usually stated not to 

 occur at all. Owing to the great difficulty of obtaining 

 embryos and young, our knowledge on these points is in- 

 complete. However, Professor Dendy has recently to a 

 large extent overcome this difiBculty, and most of the ma- 

 terial on which this investigation is based was sent to Ensf- 

 land by him. In my endeavours to clear up the points at 

 issue, I have been greatly indebted to Professor Howes and 



VOL. 44, PART 2. NEW SKRIES, L 



