REPRODUCTION, VEGETABLE (VEGKTABI.K OVUM). 



215 



present well-marked distinctive peculiarities 

 of structure. The frond consists of olive- 

 coloured, irregularly divided JlubcUi, on each 



Fig. 131. 



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the resulting cavities, zoospores are to be 

 (bund, which, though they altogether resemble 

 in structure those of the other olive-coloured 

 Algas, are about three times as large. The 

 supposed antheridia of Cutleria communicate 

 to the tufts of which they form a part, their 

 characteristic orange colour. The organs 

 themselves are elongated, sausage-shaped 

 vesicles: they contain a greyish, granular 

 matter, in which, as the organ becomes ripe, 

 indications may be observed of a division into 

 several concentric layers ; the more internal 

 of these layers being distinguished from those 

 next the surface by the greater intensity of 

 the orange colour which they present. After 



Fig. 133. 



a, a portion of one of the tufts, or sori, of Cutleria, 

 showing the mode of attachment of the filaments 

 which support the sporangia to the surface of 

 the frond ; *, a ripe sporangium. Two others, 

 half ripe, are also seen. Each is divided into 

 eight compartments, in each of which is formed 

 a zoospore, 200 diam. ; b, zoospores ; c, the same 

 in various stages of germination ; the earliest 

 stage to the right, 300 diam. 



side of which, tufts (son'), consisting of the 

 reproductive organs, intermixed with hair- 

 iike bodies, are scattered at irregular intervals. 

 The sporangia, and so-called antheridia, are 

 borne by different individuals, but their po- 

 sitions and arrangements on the frond are 

 identical. The former consist of oblong or 

 club-shaped bodies, which are supported by 

 hyaline pedicles, set into their inferior extre- 

 mities. The cavity of each sporangium is 

 divided by three transverse partitions into 

 four cavities, each of which is again bisected 

 by a longitudinal median septum. In each of 



Fig. 13-2. 



Contents of ewtheridium of the smue, 400 diam. 

 Each antherozoid is an oval hyaline corpuscle, 

 which moves in the direction of its long axis. It 

 exhibits towards its posterior extremity a 

 coloured granule, from which springs a pair of 

 cilia of unequal length. The longer of the two, 

 which oscillates rapidly, is directed forwards ; the 

 shorter, which is motionless, backwards. 



the discharge of the contents of the antheri- 

 dium, it may be observed to consist of a 

 transparent vesicle, which, like the analogous 

 female organ, is divided by transverse and 

 longitudinal septa into eight communicating 

 cavities. 



8. With the organs last described we think 

 we need have little hesitation in comparing 

 the structures to which the same name has 

 been applied, as they occur in the Fucaceas. 

 The fructification of these plants is, as is well 



Portion of one of the sori of the male plant of the 

 same. 



The ripe sausage- shaped vesicles, which contain 

 antherozoids, are shaded. Others are shown 

 which have already discharged their contents, 

 180 diam. The transverse markings, much too 

 distinct in the engraving, indicate a tendency to 

 the formation of compartments similar to those 

 wliich present "themselves in the sporangia. 



a, antheridia from the conceptaele of Halidrys sili- 

 quosa, with the filaments on which they are sup- 

 ported, 200 diam. ; b, antherozoids, 400 diam. 



known, enclosed in spherical cavities, situate 

 under the epidermis of the frond, which are 

 called conceptaclcs, and may lie male, female, 



r 4 



