252 Analytical Notices of Boohs, 



of certain errors which have hitherto prevailed with respect to the 

 subjects which they embrace. The author proves the existence of 

 deciduous canine teeth in the Horse, those of the upper jaw being 

 placed at some distance behind, while those of the lower imme- 

 diately adjoin, the last incisor. He also furnishes a history of the 

 respective periods at which the permanent molar teeth of the 

 sheep appear in succession ; the whole of them having, according 

 to his statement, penetrated the gums before the expiration of 

 the third year of the animal's age, although previous authors had 

 concurred in referring them to so late a time as the fifth year. 

 This subject, though not without its zoological interest, is evi^ 

 dently more calculated for the traders in those animals, and we 

 may therefore be excused from dwelling on it with minuteness. 



We have next to notice a paper by Dr. F. Rosenthal, " Uber 

 die Sinnes-organe der Seehunde," which contains many curious 

 particulars relative to the anatomy of the genus Phoca. From 

 the introductory observations we gather that the author is en^- 

 gaged, in conjunction with Professor Hornschuch, on a Monograph 

 of the genus ; and from their united labours, added to those of 

 M, F. Cuvier, we may expect to derive much valuable informa- 

 tion with regard to the habits and manners, (which they appear 

 to have carefully studied,) as well as the scieutific arrangement of 

 this long neglected groupe. 



M. J, van der Hoeven's " Corrections au Memoire sur le 

 genre Ornithorhinque," are the result of his examination of the 

 four individuals preserved in the Parisian Museum, Of these, one 

 is a male of the Ornithorhynchus rufus of Peron, and two are 

 males, and the remaining one a female of the O./uscus of the 

 same able naturalist. From the skeletons of these animals M. 

 Van der Hoeven has ascertained that he was in error in adverting 

 to the form of the lower jaw as a distinguishing character between 

 the species ; an error which originated in the alteration in the 

 appearance of the beak, produced by the irregular desiccation of 

 tlve membrane covering it. He obtained no additional confirma- 

 tion of the value of the character derived from the tail ; but that 

 deduced from the form of the spur in the males, on which he had 

 previously laid little stress, was strongly confirmed, that orgap 



