356 ME. C. T. DEUEET ON A SINGULAR MODE OE 



gonia were found in the usual place and number, but so far 

 neither of us was able to detect antberidia. Early in May, bow- 

 ever, I succeeded in finding a single autberidium; and it is manifest 

 tbat many others must have been present on the protballi not 

 examined, as on May 21 the final stage was reached. Small 

 fronds being visible in several cases, projecting from the bifur- 

 cation of the prothallus, and evidently therefore produced from 

 the archegonia by the ordinary sexual mode of reproduction; 

 though the prothalli, as has been shown, had developed from 

 growths that differed widely from spores in their form, their size, 

 persistent adherence to the pinnae, their production of root- 

 hairs from their surface, and, finally, the development of the 

 prothallus from their apices by simple extension of growth. 



Lest it might be assumed that these prothalli may after all 

 have resulted from true spores scattered amongst the excrescences 

 described, it should be borne in mind, first, that no spores or 

 spore-cases could be distinguished when the pinnae were laid 

 down ; secondly, that all attempts to raise this Fern from spores 

 have failed ; and finally, that the entire development of the pro- 

 thallus from the pointed tip of the pear-shaped pseudobulb — 

 its dilation, bifurcation, and gradual assumption of the true 

 prothallus-form — has been carefully watched and noted step by 

 step, not merely in one case, but in many, in all of which the 

 prothallus was evolved in the same way precisely. 



Where, as in this case, the whole phenomenon is new to the 

 observer, many points of interest are apt to be overlooked, their 

 importance being unknown until too late. Another season's 

 growth may therefore confidently be expected to throw more light 

 upon this development, and especially in relation to the first 

 appearance of the pseudobulbils themselves, which only came 

 under close observation when already of considerable size. 



In framing this account of the occurrence, I have confined 

 myself as strictly as possible to a simple and, I hope, clear record 

 of the phenomena observed during the various stages of growth 

 of the abnormal sporoid excrescences under observation. In con- 

 clusion, however, I may be permitted to point out, in connection 

 with such phenomena that, so far as formal records are concerned, 

 the family of Athyria has hitherto been remarkable for the 

 nonproliferous character of. the fronds, which, considering, first, 

 its near relation to the Asplenia, so many of which are profusely 

 proliferous, and, secondly, the protean nature of the family itself, 



