228 THAXTER. — MONOGRAPH OF THE LABOULBENIACE^. 
which the appendage is remarkably developed, yet the host is a fly which may be assumed to spend most 
of its life, at least, in the free air, although it is said to be riparian. 
Male Sexual Organs. A general division of the Laboulbeniales was formerly made by the writer 
on a basis of the differences which appeared to exist in the method of abjunction of the sperm-cells; those 
in which the latter were endogenously formed, being discharged free from a specialized antheridial cell, 
" Bndogense", and those in which they appeared to be exogenous branchlets, or segments of branchlets, 
separated from the appendages, "Exogense". It appears somewhat doubtful, however, whether this 
distinction can be as clearly drawn as was. at first supposed, in view, particularly, of the conditions seen 
in Coreomyces, a genus wry remarkable in its structure and development. The antheridial cells in this 
instance, are merely undifferentiated cells of secondary appendages arising as branches from special 
cells of the receptacle lying below the origin of the proearp, and not corresponding to any portion of the 
primary appendage, which is wholly obliterated during the development of the perithecium. As in 
Rkynckophoromyces rostratus, (Monograph, Plate XXIV, figs. 21-24), the antheridial cells are in- 
tercalary as well as undifferentiated; but in the present instance develop a short cylindrical neck through 
which free spcnn-cells are discharged very much as in the endogenous forms. That there is a gradual 
transition, rather than a sharply defined line of demarcation between these two general types, is further 
suggested by the conditions seen in Hydwphilomyces, the species of which were formerly included in 
Ceratomycrs. If the structures represented on Plate LXVIII, figs. 3-4, are in reality antheridia, we have 
here a type that, although in many respects it corresponds closely to that of the Ceraiomycev-group 
which is likewise aquatic, discharges its sperm-cells free, from cells which are almost as distinctly spe- 
cialized as arc those, for example, of Compsomyces or of Edeinomyrr,; Plates XLII1, fig. 12 and LI, fig. 
18. The antheridia of Kainomyces and Euzodwmyccs, genera the near relationship of which to Zodi- 
omyces may be assumed, are as yet unknown, owing to the imperfect character of the material available. 
Neither is the nature of the male elements absolutely determined in Ceratomyce*, or in Autoicvmyces, in 
both of which they appear, however, to be segments of certain slender branchlets. The conditions exist- 
Ing m the genus Misgomyres also, which may be related to these forms, are still unknown; so that, as far 
as any definite production of exogenous male elements is concerned, it must be confessed that it is defi- 
mtely known only in Rhynclwphyromyces and Zodiomyces. Until the exact conditions can be determined 
in the cases above referred to, this general distinction must remain of doubtful value, and in attempt- 
ing to construct a key which should at the same time indicate in a general way the relationships of the 
genera the mam divisions have been based on the differentiated or undifferentiated character of the antheri- 
dial cells a distinction which, however, can be considered by no means absolute, since it might exclude 
from the latter class Ifydrophilomyres, a genus, as above suggested, apparently most nearly related to the 
Leratomt/res-gvoup. 
A further general distinction was made in the group of so-called Kndogcn;,, baaed on the compound 
or sunple nature of the antheridia: the « mp ,c type consisting of ceils indeterminately placed, or more 
or less denmlely assoctated, free, or at least with free and independent efferent tubes; the compound 
ype mvolvmg not only the definite association of several or many antheridial evils in a determinate group, 
specfie ,„ „ s character, but also a different method of discharge; the efferent tabes of all the antheridial 
ex Yr'7'" 8 - ' " an,herilli " m ' "P*** in '° * common cavity, when,,, the sperm-cells make their 
through a angle opemng or passage j^^ ^ ^^ ^ (o ^ ^^ ^^ ^ 
