428 



Fossil Teeth. — These, Kke the fossil woods and bones before 

 named, may be mounted on slides, with or without being 

 covered with Canada balsam ; many of them, however, differ 

 but little from the recent specimens, but those of extinct 

 races of animals exhibit some very remarkable peculiarities, 

 and should, in all cases, be carefully examined, as from the 

 structure of a tooth alone the class of an animal has more 

 than once been determined. Those who would wish to enter 

 minutely into the examination of recent and fossil teeth, 

 should consult the admirable Odontography of Professor 

 Owen. A few interesting specunens of the teeth of different 

 animals are here enumerated : — 



Shell. — The structure of shell has only lately attracted the 

 attention of microscopists, but since the year 1842 the subject 

 has been scientifically investigated by Mr. Bowerbank and 

 Dr. Carpenter ; to the latter gentleman, more especially, we 

 are indebted for several valuable papers in the Transactions of 

 the British Association, to which the author begs to refer 

 those who may wish to enter fully into the subject. The 

 method of preparing these interesting structures for examina- 

 tion has already been detailed at page 331, it only remains 

 to give a Hst of the genera and species that should be selected, 

 in order to exhibit the principal peculiarities in structure, as 

 described by Dr. Carpenter ; these are as follows : — 



Anatina olen, Lima scabra, Pinna marina, 



Anomia ephippium, Lingula anatina, nigrina, 



Avicula margaritacea, Malleus albus, fibres of, 



Etheria, Mya arenaria, Pleurorhynchus, 



GerriUia, Ostrea edulis, Terebratula, 



Haliotis splendens, Pema ephippium, Trigonia, 



Hippurite, Pinna squamosa, Unio ocoidcns. 



