Imperial Institute of France. 391 



«!vvays grouped, M. Cuvier concluded ihat there exist 

 among animals four principal forms, the first of which is 

 that with which we arc acquainted under the name of ver- 

 tebral animals, and of which the other three are nearly com- 

 parable to it by the uniforntity of their respective plans. 

 The author denominates them mollusci, ariicnlalcd animals, 

 and radiated animals or zoophytes, and subd.vidcs each of-, 

 these forms or ramifications into four classes, according to 

 motives nearly equivalent to those upun which the four 

 classes rest which are generally adopted among the verte- 

 bral animals. He has derived irom this in some measure 

 sy^imetrical arrangement, a great facility in reducuig under 

 general rules the diversities of organization. 



The com[)ari5on uhiclj the same member has drawn of 

 the osteology of vertebral animals, has furnished him with 

 some new ideas as to the osseous structure of the head in 

 this branch, and which he has also presented to the Class. 



It had been long since ascertained 'hat oviparous veite- 

 bral annnals, ?'. e. birds, repides, and fishes, had several 

 comn)on relations of organiz,^tlon, which made them differ 

 from the viviparous or mamn)iferous vertebral animals ; 

 M. Geoffroy Samt Hilaire had ewn presented some years 

 ago an extensive and elegant work, of which we tjave an 

 acc(>unt at the time, ni which he proved among other 

 tilings the identitv of structure of the heads of all the ovi- 

 paii, and the relations of the numerous pieces which enier 

 i<ito their composition, with tho^e which we distinguish in 

 the foetus of the maminifLrae, in which, as is vacII known, 

 the bones are much more subdivided than in adults- 



M. Cuvier, adopiing the views of M. Geoffroy, has en- 

 deavoured lo deieriniiie in a certain manner, to vn hat bone 

 of the head of she maiumiferiE each groupe of bones of ihe 

 head of the difiercni ovipari answf r> ; and he thinks he 

 has attained ilTis, by adding to ihe analovv of (he fcetus of 

 llie former, the consideration of the position and of the 

 functions of the hones: i.e. by examining what origans 

 they protect, to what nerves and vessels they give a passage, 

 and what muscles are attached to them, 



M. Jacobson, surgeon major in the armies of the king 

 of Denmark, has made the Class acquainted with an 

 organ wliich he discovered in the nostrils of quadrupeds, 

 and with which no anatomist seems to havp been ac- 

 quainted. It consists of a narrow sac, lying along ihe 

 cavity of the nostrils, defentled by a eariilaginous pr(»- 

 <luclion, covered internally by a mucous membrane, 

 doubled in pari by a glandulnus texturt, rectivipg some 



B b A very 



