1906] LEWIS—DEVELOPMENT OF RICCIA 119 
Kwy (19). The mature antheridium’ is a short stalked oval body 
with a conical apex. 
As the antheridium develops, the vegetative tissue grows up and 
surrounds it so that it is enclosed in a cavity which opens into the 
dorsal furrow. This cavity is formed in the same way as the air 
spaces of the thallus. The apex of the antheridium is a little below 
the floor of the dorsal furrow and the sperms escape through the 
neck formed by the surrounding tissue. Although the antheridia 
begin to develop in autumn, they are not mature until the following 
spring, because the growth is checked by the cold. Plants kept in 
a warm place produced mature antheridia during the winter. 
A series of archegonia is developed which is a continuation of 
the series of antheridia (fig. 7). The archegonium is at first super- 
ficial on the floor of the dorsal furrow. Later it becomes enclosed 
in a cavity by the upward growth of the vegetative tissue as in the 
case of the antheridium except that the neck of the mature arche- 
gonium protrudes above the bottom of the furrow. The origin of 
the archegonia side by side at the bottom of the dorsal groove is 
Shown in figure 9. In this way three to five rows are formed and 
later a large number of sporophytes are found in each thallus. 
The archegonium develops in general as has been described by 
JANCZEWSKI (17). My observations confirm the account given by 
GARBER for Ricciocarpus natans, as a comparison of the figures 
will show, so it is unnecessary to describe the development here. 
About the time when the archegonia are mature, cross-sections 
of the thallus show numerous, delicate, almost hyaline, club-shaped 
hairs extending up from the floor of the median groove. Each 
hair consists of a stalk of two or three short, narrow cells with a 
much larger cell at the free end. These hairs bear a striking resem- 
blance to paraphyses(jig. 78). LEITGEB (22, p.31) describes ‘‘papillae’”’ 
which grow up from the bottom of the groove and regards it as 
highly probable that it was the dried remnants of these which LINDEN- 
BERG observed when he wrote: “Sporangium vor aussen mit kleinen 
unregelmissigen braunen Schuppen bedeckt ist, die Fragmente 
einer zersprengten friiheren Hiille zu sein scheinen.”” As the hairs 
become older they become brown and break down so that they 
