Thraustotheca, a Peculiar Water-Mould. 
173 
Fig. 48. Germination of an oogonial gemma by hyphae. x 550. 
Fig. 49. Two adjacent oogonium initials; one, with diclinous antheridium attached, has formed 
oospores; the other, without antheridia, has formed a sporangium, x 550. 
Fig- 5 °* Formation of oospores in an oogonium which, after proliferating once, has been reached 
by a diclinous antheridial filament, x 550. 
Fig. 51. Intercalary oogonium showing large pits through which fertilizing tubes have entered, 
x 550 - 
Fig. 52. Two hyphae of similar origin, one of which formed an antheridium on reaching an 
oogonium ; the other formed a sporangium, x 150. 
Fig* 53* Androgynous antheridium on an oogonium, x 550. 
Figs. 54-6. Stages in the development of oospores in an oogonium, x 550. 
Fig. 57. Later stage in maturation of an oospore, x 1,400. 
Fig. 58. Mature oospore, x 1,400. 
Figs. 59, 60. Changes in oospore preliminary to germination, x 1,400. 
Fig. 61. Formation of germ-tube by free oospore, x 1,400. 
Fig. 62. Formation of a mycelium by oospores germinating in situ, x 350. 
Fig. 63. Formation of a sporangium by an oospore germinating in situ, x 550. 
Fig. 64. Hyphae of germination from oospores in situ growing out through the empty 
antheridia. x 1,400. 
