116 PHTCOMYCETE AE 



by antherids of androgynous or diclinous origin. The oogones have few to 

 many papillae about 2 n thick and of variable length up to 20 n. The 

 fungus occurs on keratinized material in the soil and may be cultured on 

 thin slivers of horse hoof. 



Apinis (1935) described a genus which he named Archilegnia in which 

 fertilization is claimed to be by motile uniflagellate sperm cells. In other 

 respects such as the mode of asexual reproduction and the structure of 

 the pluriovulate oogones this fungus is like Saprolegnia. Not only do the 

 sperms arise in short antherids growing out at right angles from the main 

 hypha, but the author claims that encysted zoospores may give rise to 

 four sperms. He reports that the sperms enter the oogone through small 

 openings. It is likely that this genus was described from a Saprolegnia 

 parasitized by small Protozoa or Chytridiales. If the correctness of the 

 reports of Apinis can be confirmed it will throw great light upon the 

 possible ancestry of the Saprolegniaceae. 



Family Leptomitaceae. In this family the mycelium is slender as in 

 the foregoing family, but is constricted at more or less regular intervals. 

 The constrictions are sometimes plugged by granules of carbohydrate 

 nature to which the name cellulin has been given. Similar granules may 

 be found scattered in the cytoplasm. The cell walls give the cellulose reac- 

 tion immediately when treated with chloriodide of zinc. The zoospores are 

 dimorphic. The oogones contain no periplasm. In Apodachlya there is 

 only one egg in the oogone but in Apodachlyella there are several. All the 

 known species of the family are saprophytic, chiefly on matter of vege- 

 table origin. Some species are aquatic, growing on sticks, fruits, etc.; 

 others grow unattached in water rich in organic matter; and some grow 

 in soil. 



Leptomitus, of which L. lacteus (Roth) Agardh is perhaps the only 

 species, consists of branching, cylindrical hyphae rather uniform in size, 

 found in water containing large amounts of organic matter, such as 

 drainage water from sugar factories, near the mouths of sewers, etc. It is 

 easily distinguished by its constrictions which may remain open or become 

 plugged by granules of cellulin. The terminal segments first and then 

 successively the segments behind them become converted into zoospo- 

 rangia in which are produced numerous pear-shaped primary zoospores 

 all of which may escape successively through the terminal zoosporangium 

 or from separate openings from each zoosporangium. The zoospores 

 scatter as do those of Saprolegnia, eventually giving rise to zoospores of 

 the secondary type. Sexual reproduction is unknown. (Fig. 35 F.) 



Apodachlya is also much branched and has no specialized holdfast 

 hyphae. The zoosporangia are distinct from the main hyphae, and are 

 mostly ovoid or pyriform, tapering below to a short pedicel. The oogone 

 contains a single egg without periplasm and may be terminal or lateral. 



