Rev. J. B. Reade on Organic Remains in Flints. 191 



above-described perfect, and almost regular subdivision pro- 

 duced by the action of boiling muriatic acid. 



Recent examinations into the development of buds have 

 shown me that that cellular lay^er which is subsequently deve- 

 loped into tubes of the liber and so-called ligneous fibre, and 

 extends as an uncoloured zone from above the medullary cone 

 to the nucleus or rudiment of the bud, consists of extremely 

 delicate, rather extended, prismatic, generally 4-, 5-, or 6-sided 

 parenchymatous cells, which stand with their ends accurately 

 one above the other, and are gradually converted by the ab- 

 sorption of their septa into the long fibrous cells or tubes of 

 the liber. The regular abrupt cylindrical tubes into which 

 the fibres of flax were decomposed by boiling in muriatic acid^ 

 are almost exactly of the same length as these tender paren- 

 chymatous cells in their fully developed state ; and that the 

 latter originate fi*om the delicate cells of the medullary sub- 

 stance by gradual extension, may easily be obsei'ved in the ter- 

 minal buds of the horse-chestnut and of the ash. 



On the absorption of the septa of those cells, the superposed 

 edges grow so intimately together that their union has not 

 hitherto been observed, and the tube thus originated forms the 

 first or fundamental layer of the membrane of the fibrous 

 cell, the thickening of which follows as usual by deposition 

 of new layers on the inner surface. I am induced to pub- 

 lish these short notices at present, as they may afford some 

 indications tending to explain the origin of the fibres of the 

 muscles and nerves of animals ; at the same time I would re- 

 commend a careful attention to the spiral formations which 

 muscular fibre exhibits often quite as plainly as the tubes of 

 the liber. It also appears to me that distinct layers are per- 

 ceptible in the membrane of the muscular fibre of fish. 



XXIV. — On some nevj Organic Remains in the Flint of Chalk. 



By the Rev. J. B. Reade, M.A., F.R.S. With Plates VIII. 



and IX. 

 It is now very generally admitted that a geologist is as much 

 in need of a microscope as of a hammer. Instruments of the 

 latter class may indeed be sufficient for the exhumation of the 



