12 Mr. J. Miers on the Development 



this metamorphosis in almost all the embryos. Does this trans- 

 formation of the ciliated embryo into a young Acineta always 

 take place ? It is allowable to doubt this ; twice I have seen 

 ciliated embryos become enclosed in a cyst, instead of changing 

 into young Acineta. I was unable to carry the observation 

 further, and ascertain whether or not the Infusorium underwent 

 new transformations in the interior of the cyst. Further re- 

 searches are required to clear up this obscure question. 



II. — On the Development of the Vegetable Ovule called ' Ana- 

 tropous' By John Miers, F.R.S., F.L.S., &c. 



Although the changes that take place in the development of the 

 vegetable ovule have long since occupied the attention of the ablest 

 physiological botanists, it is evident that the real nature of its mode 

 of growth is not yet well understood. My first object therefore 

 is to show that the doctrine upon this important subject, as 

 taught in the best elementary works, is founded upon a very grave 

 error. I was led into this inquiry by my desire to ascertain the 

 nature of the fleshy covering enveloping the hard tunic in certain 

 seeds *, and which appeared to me arilloid in its nature. This was 

 contested by Dr. Asa Gray, who considered these two very oppo- 

 site kinds of tunics as one baccate testa, both deriving a common 

 origin from the primine of the ovule f. To this view I was un- 

 willing to subscribe ; and in my subsequent discussion of the 

 subject, trusting fully to the orthodoxy of the common creed of 

 botanists on the development of the ovule, I argued % that the 

 fleshy covering in question must be an expansion or growth of 

 the placentary sheath, because it enclosed the raphe : and so it 

 is undoubtedly — but not in the light of an extraneous expansion, 

 as I then viewed the question. This induced me to examine, by 

 personal observation, the actual progress of growth of the ovule 

 in certain plants which produce what have been called anatropal 

 seeds ; and I soon became convinced that I had been led into an 

 error of inference, solely by my faith in the universally prevalent 

 creed. Having lately completed the investigation of many 

 Rhamnaceous and Anacardiaceous seeds, in which several novel 

 points of structure have been observed, which are difficult to 

 explain, I am desirous, before the publication of these results, 

 that the real nature of the development of the ovule should be 

 well understood. I therefore now proceed to show that the 

 doctrine upon this subject, as at present taught, is completely 

 fallacious. 



♦ Trans. Linii. Soc. xxii. 81. f Journ. Linn. Soc. ii. 106. 



X Ann. Nat. Hist. Srd ser. i. 276. 



