28 SHACHT, ON SPERMATOZOID IN THE VEGETABLE KINGDOM. 
minute, elongated, rounded or pointed cell, which, at a definite 
spot, supports one, two, or more cilia, often of unequal length. 
Its movement consists in a rotation on its axis with 
the cilia in front; and in some species it presents a cell- 
nucleus. 
5. In the Equisetaceee and Ferns the body of the spermato- 
zoid has the form of a sausage-shaped or half-flat band, which 
gradually widens from before backwards, and hes rolled up 
like a watch-spring in the interior of the parent-cell; but 
when liberated it assumes a closely twisted spiral form. In 
the Equisetaceze the body of the spermatozoid is thicker and 
shorter than in the Ferns. The spermatozoid of Isoetes ap- 
pears to belong to the same type, and probably that of the 
Rhizocarpee. 
6. In the Characeze, Musci, and Lichens, the spermatozoid 
has a sausage-shaped very slender body, which, like that of the 
Equisetaceee, &c., is rolled up like a watch-spring within the 
parent-cell, but on its liberation assumes more of a corkscrew 
figure. The length of the spermatozoid body, and, corre- 
spondingly, the number of its spiral turns, varies in different 
species or genera. In the Characes the parent-cells of the 
spermatozoids are united into long confervoid filaments in the 
interior of the antheridium; in the mosses and lichens, how- 
ever, the parent-cells constitute at first a dense tissue in the 
interior of the antheridium, but afterwards appear as free 
cells, whose membrane is either ruptured by the spermatozoid, 
or undergoes solution in the water. 
Consequently we may distinguish THREE typical forms 
of spermatozoids, viz:—1l, that of the Alge; 2, that of the 
Equisetacee ; and 3, that of the Characez. And, moreover, 
as regards germination and the mode of development of the 
reproductive organs, an intimate relationship may be ob- 
served in the families belonging to each of these types. Thus, 
in the Algze we find the simplest reproductive organs, and a 
direct germination; in the Equisetacean type, under which 
are included the Ferns, on the other hand, we observe the ex- 
istence of the complex reproductive organs on a prothallium ; 
or, if the Lycopodiaceze and Rhizocarpez are conjoined with 
these families, we also witness the appearance of the female 
organ on the same prothallium. Lastly, in the Characean 
type, although similarly constructed, reproductive organs 
make their appearance on the fully developed plant; no 
direct germination ensues, but rather the production of a 
prothallium, from a budding out of which arises the young 
plant. This type stands midway between those of the Alge 
and of the Equisetaceze. 
