Exogenous Seeds and Fern Spores. 333 



sliding tube, the two links may be separated or approximated 

 so as to give a greater or smaller magnification/'' 



M. Chevallier's work is, in many respects, well executed ; 

 but we regret that in describing the Infusoria he follows the 

 classification of Miiller, according to which rotifiers are con- 

 founded with the vorticellids, because both make whirlpools 

 by means of their cilia, a fact not quite true of the floscularians, 

 and which, taken by itself, affords little clue to either affinities 

 or structure. 



EXOGENOUS SEEDS AND FEKN SPOKES.* 



BY E. DAWSON, M.B., LONDON. 



(With a Tinted Plate.) 



Balfottk, in his Manual of Botany, says, "The embryo varies 

 in its structure in different divisions of the vegetable kingdom. 

 In Acrogenous and Thallogenous plants it continues as a cell 

 or spore, with granular matter in its interior, without any 

 separation of parts or the production of cotyledons. Hence 

 these plants are called Acotylcdonous." 



Further on he says, ". The spore of Acotyledonous plants 

 is a cellular bodjr, from which a new plant is produced. Ger- 

 mination takes place in any pari of its surface, and not from 

 fixed points." 



Moore, on British Ferns, defines spores much the same ; 

 describing the determined points in seeds, the cotyledons, the 

 ascending and descending axes, and then, contrasting the 

 development of ferns' spores, says, " On the contrary, they 

 consist merely of a small vesicle of cellular tissue, growing 

 indifferently from any part of its surface" (Hand-look of British 

 Ferns). Carpenter on the Microscope, Lindley's Vegetable 

 Kingdom, etc., all have a like idea. The above, then, is the 

 received opinion of the present day relating to the growth of 

 the fern spore. See also Hofmeister's elaborate work, published 

 by the Kay Society. 



These same high authorities also state and believe that 

 ferns germinate by bodies called antherozoids or males, coming 

 into connection with archegonia or females, and this occurs on 

 the first-formed body from the spores, called prothallium. 



The first part of those statements, as far as I can learn, 

 has never been questioned ; the latter has, though now uni- 

 ally accepted. I proceed to disprove the first statement 

 entirely, and I hope to throw discredit on the last. 



A seed in its simplest form, such as seen in the mistletoe, 



* This paper was read before the Brighton and Sussex Natural History Society. 



