XI 



THE HOMOSPOROUS LEPTOSPORANGIAT.-E 



345 



in Ofioclea, but the number of sperm cells is larger, being 

 usually lOO or more. The development is also the same, and 

 will not be entered into here.^ After the final division of the 

 sperm cells the nuclei remain slightly flattened in the plane of 

 division, as in the Hepaticae, and the mature spermatozoids 

 are coiled more flatly than in the Polypodiacea^. The free 

 spermatozoid recalls that of Marat tm or Eqitisetian rather than 



Fig. 174. — A, Ripe antheridium of O. Claytoniana, just ready to open ; B, the same disch 

 sperm cells, x6oo; C, two spermatozoids, X 1200. 



the Polypodiaceae. There are but about two complete coils, 

 and the hinder one relatively larger than in the latter forms. 

 In swimming there is peculiar undulating movement, suggestive 

 of the spermatozoid of Equisetuvi. 



The Ardiegoniuiii 



The archegonia are only borne upon the large heart-shaped 

 prothallia, and occupy the sides of the projecting midrib, where, 



1 I'or details see Campbell (12), p. 61. 



