324 APPENDIX. 



I dissected at the London Zoological Society's Museum 

 (Proceedings of the Zool. Soc. 1838, p. 41), the skull, 

 a section of which is figured in my « Odontography/ pi. 

 92, measures 14 inches in length: the deciduous inci- 

 sor and the first molar are still retained : the fourth molar 

 has come into use : the rough summit of the last molar is 

 through the bone, but, apparently, had not pierced the gum. 



The first molar in both the above specimens of Halicore 

 indicus has a crown 2 lines broad ; the second molar is 

 3 lines broad ; the antero-posterior extent of the four first 

 sockets is 1 inch 5 lines in both specimens. 



The above admeasurements are taken from the upper 

 jaw, and there is not any trace of a socket anterior to the 

 first small molar in either upper or lower jaw of either 

 specimen of the Indian Dugong. 



The germ of the last (fifth) molar in the skull of the 

 younger individual (Home's), shews the beginning of the 

 lateral channels which occasion the characteristic bilobed 

 form of its summit, or transverse section. If, at a still 

 earlier period, there be a molar anterior to the first small 

 one in place in the Halicore indicus, it must be extremely 

 minute, a mere rudiment manifested only in the substance 

 of the gum, and leaving no trace of its existence upon the 

 alveolar border of the jaw. 



These observations and comparisons led me, in 1840, to 

 adopt the conclusion to which Cuvier had arrived from his 

 examination of the rich series of skeletons of the Halicore 

 indicus in the Paris collection, as to the numerical formula 

 of the molar teeth : viz., that not more than twenty are 

 developed, five on each side of both upper and lower jaws: 

 expressed by the formula, f J = 20. 



But this formula must now be regarded as characterising 

 the species of India and the Red Sea, not the genus 

 Halicore. 



