60 LINDSAY, ON ABROTHALLUS. 



by a simple or stellate ostiole or pore, with flat^ more fre- 

 quently raised, and sometimes, but rarely, depressed borders. 

 Even under tlie lens, and especially in young spermogones, 

 the pore is often imperceptible. It may be made more 

 prominent by moistening the spermogone, whose tissue is 

 very hygrometric, swelling rapidly and greatly in water ; the 

 ostiole becomes thus more patent, and its edges better 

 defined. With age also the ostiole becomes more open and 

 generally stellate, the cavity of the spermogone being empty 

 and its walls hardened. In old spermogones also the de- 

 pressed or saccate character of the ostiole is occasionally 

 observed. The ostiole leads into a somewhat spherical and 

 simple cavity, whose envelope consists of a brown cellular 

 tissue, and whose internal walls are lined by a compact series 

 of sterigmata, — arranged perpendicularly to the spermogonal 

 walls, and convergently to the centre of the spermogonal 

 cavity, — generating from their apices myriads of spermatia. 

 When moistened, the spermogones assume a light brown tint ; 

 and Avhen the thallus or matrix is moistened and viewed by 

 transmitted light, they constitute a series of brownish, 

 translucent, round spots, amid the surrounding dull opaque 

 green (of the gonidic layer shining through the brownish 

 cortical tissue). The sterigmata are simple, cylindrical, or 

 almost linear cells, frequently very irregular in form, being 

 sinuous in their outline, and presenting bulgings or bendings. 

 On tracing carefidly their connection with the walls of the 

 spermogone, they appeared to me to be given off as a series 

 of hollow Ijuds, at irregular intervals, from a peculiar tubular 

 tissue. The wall of the parent-tube presented a bulging 

 which became dilated and elongated into the form of a 

 sterigma. From the apex of the latter a smaller bud was 

 developed, which became elongated into a linear, very 

 slender, straight rod-shaped body; on attaining a certain 

 length, a septum became visible at the point of junction be- 

 tween this body, the spermatium, and its sterigma, and a 

 severance took place. The sterigmata often came off in 

 groups from the parent-tubes, and, Avhen ' elongated and 

 narroAV, not unfrequently resembled the fingers of the hand. 

 Sometimes the sterigmata were nearly as narrow as their 

 spermatia, into which they gradually tapered. The spermatia 

 were either seated perpendicidarly on the apices of the 

 sterigmata, or they came off at various angles, which were 

 occasionally very acute. In the latter case there was fre- 

 quently a bulging or dilatation of the sterigmata immediately 

 before they gave off the spermatia. 



The spermatia between about -^-^q-^ and j^'^j^ inch long. I 



