MONOGRAPH OF THIS LABOULBENIACE^IS. 



209 



of them ; and it seems certain that they do not thus act as brushes for the more con- 

 venient transfer of these bodies. In general the ultimate filamentous sterile branches, 

 or branchlets, consist of a single series of superposed cells which appears to elongate, 

 at least in so far as I have been able to determine, through the successive division of 

 the terminal cell. 



One curious structure, the significance of which is as yet undetermined, should be 

 mentioned before leaving the sterile portions of the appendages. This structure con- 

 sists of a spine-like process laterally developed from the primary appendage, and has 

 been observed in only a few instances. It is most pronounced in an apparently 

 undescribed genus parasitic on Tachinus pallipes, which has not yet been found in a 

 mature condition. It also occurs in Sphaleromyces Lathrobii (Plate XI, fig. 19) and in 

 Rhadinomyces cristalus (Plate IX, fig. 22), in both of which it seems to disappear at an 

 early period. The process which is persistent at the summit of the antheridium in 

 Haplomyces may also be of a similar nature. 



Male Sexual Organs. As has been previously mentioned, the essential function of 

 the appendage, apart from the secondary function of protection which it undoubtedly 

 subserves in many cases, is as a rule connected with the production of the male sex- 

 ual organs; although in the following genera, Amorphomyces, Dimorphomyces, 

 Diineromyces, Enarthromyces, Peyritschiella, and Dichomyces (probably also in 

 Chitonomyces and Hydrceomyces), the latter are wholly independent structures un- 

 connected with the sterile appendages which usually accompany them. 



A comparison of the character of these male organs in the different genera 

 makes it apparent that they afford the best, indeed the only basis for the natural 

 separation and grouping of the members of the family as a whole, which are thus dis- 

 tinguished into two main categories : one including those forms having male organs 

 from which the male elements are produced exogenously ; the other including those 

 forms in which the male element arises endogenously. Of these groups the first may 

 be further subdivided, on a similar basis, into forms in which the male organs are 

 borne on specialized male individuals, and those in which the sexes occur together 

 on the same individual. Again, as will be seen presently, these monoecious and dioe- 

 cious groups are further distinguished according as the male organs are simple or 

 compound ; while their relative position, distribution, etc., afford opportunities for 

 minor subdivisions. 



Since they are undoubtedly homologous with similar structures in the Florideas, 

 the male organs and male elements in the Laboulbeniacece may be properly designated 

 as antheridia and antherozoids, respectively ; the former, as will be seen, consisting of a 



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