172 THE SAPROLEGNIACEAE 



at the tip or on the side to discharge the actively motile, biciliate spores 

 which are formed in a single row, or imperfectly in two rows, and are 

 about io.5-ii[j. in diameter. They are diplanetic, a fact hitherto un- 

 certain on account of conflicting reports. Pringsheim considered them 

 monoplanetic, but Hartog ('87) was right in stating them to be diplan- 

 etic (as Saprolegnia corcagiensis) . Sexual reproduction has never been 

 observed. 



As a subject for the demonstration of protoplasmic rotation this 

 plant has no superior. Unlike the Saprolegniaceae the strongly granular 

 protoplasm is in constant motion and is easily observed even by inexperi- 

 enced students. We have found the plant in Chapel Hill not only in 

 sewers, etc., where it may be had at any time, but also rarely in such 

 clean streams as Battle's brook and the brook behind the athletic field. 



Kolkwitz ( '03) has studied the culture requirements and physiology of 

 this species, and has also published a condensed statement of his results 

 ('03a, p. 147). For illustrations see Humphrey ('92), pi. 20, figs. 115-118; 

 Pringsheim ('60), pi. 23, figs. 6-10, and pi. 25; and Biisgen ('82), figs. 

 9-15. For other cytological data see Dangeard ('90), p. 118, pi. 6, figs. 

 24-31- 



APODACHLYA Pringsheim, 1883, p. 289. 



Hyphae constricted into segments of variable length, more slender 

 than in Leptomitus, the branching taking place from any point in a seg- 

 ment, but usually near the distal end. Sporangia swollen, pyriform, 

 oval or spherical. In three species spherical resting bodies are known 

 with the contents entirely filling them, and we regard these as true 

 oogonia containing a single egg; in A. completa (probably not an Apod- 

 achlya) larger oogonia are formed with several eggs. 



Four species have been described, but in only one, A. pyrijera Zopf 

 ('88, p. 362)*, has the structure heretofore been well known. See also 

 Petersen ('10, p. 526). The others are A. brachynema (see below), ^. 

 pufidata Minden ('12, p. 586, figs, b-d on p. 580), a very doubtful species, 

 and A. completa Humphrey ('93), which was referred to this genus with 

 some doubt as the sporangia were not found. We include a description 

 of only the species we have found. For the others see the literature 

 cited above and, in addition, Fischer ('92, p. 373). 



Key to the Species 



Oogonia present, each containing several eggs A. completa 



Resting bodies (oogonia?) entirely filled by the contents which is organized like a single egg. 



* The name Apodachlya pyrijera is first used on p. 367, and the plate is labelled Lep- 

 loiiiittis pyrijera. 



