THAXTER. — MONOGRAPH OF Till: LA HOI fLBFA I AC I I 



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dously, growing, like the antheridial cells of compound antheridia, into the cavity of the adjaceni cell 

 above. Not only is this cell traversed by the procarpic, and later by the peritheeial branches, but 

 several cells above are successively penetrated, the intervening septa being perforated and destroyed; 

 the free trichogyne eventually making its way out distally and replacing the terminal primary ap- 

 pendage, which is sloughed oft'. This very peculiar condition, which is illustrated on Plate LXXI, 

 and described in detail under the genus, has no counterpart in the group. The perithecia of Zodi- 

 omyces, although the branches which produce them arise endogenously, are themselves exogenous, 

 and quite free from the beginning of their development. In (Jcrafomyces, also, although the forma- 

 tion of the perithelium is not of the ordinary type, the conditions do not appear to be in any way 

 comparable. 



The early development of the carpogonium after fertilization has been described in detail in the 

 Monograph, and appears to be similar throughout the group. The only striking phenomenon in 

 this connection that has been observed among the new forms is seen in the genus Polyascomyrrs, 

 in which the ascogenic cells become so greatly multiplied that a condition occurs not unlike that seen 

 in the perithecium of other Ascomycetes, more than thirty ascogenic cells covering a basal area from 

 which large numbers of asci bud upwards; Plate XXXVII, figs. 1-2. 



The cytology of ascus- and spore-formation has been examined by Dr. Faull who has published 

 a preliminary note in Science, already referred to, and has kindly allowed the writer to examine his 

 preparations. The latter appear to show that the phenomena involved correspond essentially with 

 those in other Ascomycetes, the ascospores being formed as a result of the divisions of a fusion-nucleus 

 by a process exactly similar to that which is normal in this type of spore- formation. Since Dr. Faull 

 has not as yet published a full account of his results, the writer does not feel at liberty to make 

 further reference to them in the present connection. 



The structure of the mature perithecium is, in all genera, fundamentally the same, except in 

 the case of the pseudoperithecium of Coreomyces, and has been given in detail in the Monograph. 

 The most important variations relate to the number of cells in each of the four outer and of the 

 four inner and alternating rows of wall-cells, and to the production of outgrowths or appendages from 

 the outer rows. A curious condition has, however, been observed in Dicliomyces, some species of 

 which show a remarkable dimorphism in their perithecia; the two forms being associated on the 

 same individual as in D. hybridus, Plate XXXI, fig. 16; or occurring, as in D. biformis, Plate XXXIII, 

 figs. 2-3, on distinct individuals. In both these instances it will be observed that the two varieties 

 are not only unlike in size and form, and to some extent in color; but that, while in one auricle- 

 like outgrowths are present, these are wholly absent in the other. Two forms of perithecium also 

 appear to occur in Rhizomyces crispatus, Plate LII, figs. 19-20, although in this instance it is barely 

 possible that two species are concerned. It is possible that the dimorphism in D. hybridus, may 

 have resulted from hybridization, for example between a form like D. fureiferus and the common extra- 

 Asiatic from of D. hybridus, which is not known to possess auricles. This dimorphic condition, how- 

 ever, appears to occur in other species, and it seems unlikely to the writer that it can be explained 

 in this way. Among instances in which the perithecium may show wide differences in form in a 

 given species, Laboidbenia Poiyhirmcc may be mentioned, Plate LXV, figs. 1-3; and the varieties of 

 L. Texana, if these are rightly separated merely as varieties, show very remarkable conditions in 

 this respect, Plate LXIII, figs. 3-9. 



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