497 



divisi da quelli delle grandi cellule piramidali per mezzo della scissura 



deir Hippocampo, riesce talora abbastanza facile di aprire la 



scissura dell' Hippocampo e scorgere cosi le irregolarita che la circo- 

 scrivouo." 



Oltre la memoria ora riassunta, ne troviamo un altra in cui si 

 fa brevemente cenno dei prolungamenti papillari. — Carthy^) li di- 

 mostro colla dissezione nel cervello umano, pero senza ben com- 

 prendere con quali parti della formazione ammonica fossero in con- 

 nessione; quest' A. crede il suo reperto aflfatto nuovo, 



Firenze, 26 Agosto 1904. 



Nachdruck verboten. 



Numerical vertebral Variation in the human Adult and Embryo. 



By Charles R. Bardeen, Professor of Anatomy, 

 the University of Wisconsin, Madison. 



Rosenberg in 1876 advanced the hypothesis that in man the 

 sacrum is at first composed of a more distal set of vertebrae than 

 those belonging to it in the normal adult condition and that during 

 development lumbar are converted into sacral, sacral into coccygeal 

 vertebrae. In other words, the iliac attachment of the limb skeleton 

 is supposed to advance along the spinal column during ontogeny. This 

 change of position is believed to correspond to a similar one that has 

 taken place in the phylogeny of man. 



Rosenberg also described a rib as occurring regularly on the 

 20th vertebra (normally the 1st lumbar) at an early stage of deve- 

 lopment. In a later paper (1882) he gave a description of a cervical 

 rib formed regularly in the 7th and occasionally in the 6th cervical 

 vertebra in young embryos. From these data he concluded that there 

 is an ontogenetic reduction of the number of rib-bearing vertebrae, 

 which but repeats phylogenetic history. 



Variation in the adult, according to Rosenberg, is due largely 

 to a failure during ontogeny to carry the processes of reduction above 

 mentioned as far as they are usually carried in the race, or to their 

 being carried beyond this limit. 



In spite of the fact that a considerable number of investigators, 



1) Carthy, a new dissection showing the internal gross Anatomy 

 of the Hippocampus major. Journ. of Anat. and Physiol., Vol. 33, 1898. 



Anat. Anz. XXV. Aufsätze. 32 



