Observations on the Organogeny of the Flower. 403 



Species dubi^. 

 2. Acephalocystis *. Choroid i)lexus of brain in man {Homo). 



* The little transparent globular vesicles which are occasionally 

 found attached to the choroid plexus in the brain of the human sub- 

 ject are denied to be hydatids by pathologists, and are considered to 

 be merely accidental distensions of the coats of the veins in the part ; 

 I have however reason to believe that they are really Acephalocysts, 

 as they develope gemmules, which are detached from the inner sur- 

 face of the cysts. These are very small and globular, varying some- 

 what in size, the largest being visible to the naked eye like little 

 opake points ; their coats are transparent ; they were most abundant 

 upon that surface of the vesicle which was attached to the plexus ; 

 they existed in considerable numbers, and were readily detached 

 from the parent vesicle. 



The larger cysts were in many instances attached to the vein, but 

 did not communicate with its cavity. In some the external coat of 

 the vein appeared to have been expanded to form them. The fluid 

 which they contained was coagulated by alcohol. 



L. — Observations on the Organogeny of the Flower, and particu^ 

 larly of the Ovary, in Plants with a free central Placenta. By 

 M. Gaudichaud-J-. 



After some remarks on the state of organogeny at the present 

 time, M. Gaudicliaud gives the following brief summary of the 

 principles of that department of botanical science : — 



" 1. All organization commences in the cell. 



"2. Every so-called appendicular organ of vegetation and 

 fructification results from a cell endued mth vitality. 



" 3. The organized cell produces a bud of leaves, flowers or 

 ovules. 



" 4. All pre-exists in every such hud ; no fresh organization is 

 added to it, any more than to the cell. 



" 5. The order of succession of the })arts in the leaf- or flower- 

 buds, as well as in the ovules, always takes place from the circum- 

 ference to the centre. 



" There are two great organic types in vascular vegetables. Mo- 

 nocotyledons and Dicotyledons. In Monocotyledons the cells 

 always become endued v>'ith vitality one after another, one by an- 

 other, to produce distinct uuivascular individuals, which obey an 

 organogenic law yet unknown. This law, which regulates the 

 deviations and arrangements, produces what we call verticils. The 



f From a Ptcport by M. Gaudicliaud on a memoir of TJ. Ducliartre bear- 

 ing; the above tit'e, abstracted by A. Henfrey, F.L.S., from the ' Comptes 

 llendus,' Aug. 19, 1844. 



2ES 



