364 EETIEWS. 



membranes, viz. the outer and inner membrane of the spore Itself, 

 and the outer and inner membrane of the ascus or basidium, within 

 which it is produced, and to which it is adnate. If the numbers of 

 membranes covihl not be ascertained when the spores are first shed, 

 it is possible that, by inducing them to germinate, the obseryation 

 might be rendered easier.* 



In speaking of the manner in which the spores of fungi are dis- 

 persed, the authors refer to the observations of the Messrs. Crouan, 

 with regard to the opening of the asci of Ascobolus. In this genus 

 the tip of the ascus sometimes sphts at the top in a circumscissile 

 manner, and bends backwards, exhibiting the appearance of a little 

 cap or helmet thrown back and adhering by a hinge. The Messrs. 

 Crouan give figures of this mode of dehiscence in several species of 

 Ascobolus figured by them (see Annales des Sc. NatiireUes, 4th 

 series, Vol. vii. PL 4, and Vol. x. PI. 13), and they state that the cap, 

 or operculum as they call it, is often entirely detached by the rapid 

 and instantaneous escape of the spores. The MM. Crouan appear 

 to think this dehiscence worthy of special notice, as they suggest that 

 it aff'ords an additional generic character to distinguish the Ascoboli 

 from the Pezizse, and the MM. Tulasne speak of it as occurring only 

 in Ascobolus saying " Ascoboli solius, quautiun sciamus, theca ex- 

 trema rescisum dimittit galeolum." "We are incHned to think, 

 however, that the fact is not of much importance, for the same thing 

 occurs in Sphasria herbarum, where the asci have been seen to open 

 in a manner precisely similar to that observed by the Messrs. Crouan 

 in Ascobolus. A figure of the fruit of this Sphsoria, sho\\ang the 

 peculiar dehiscence of the asci is to be found in the Quarterly Jour- 

 nal of Microscopical Science, Vol. iv. PI. xi. fi". 32, 33. f 



The thick gelatinous envelope of the spores of certain Pyrenomy- 

 cetes forms the subject of a few remarks at p. 44 and 45, and refer- 

 ence is there made to a note in Nylander's " Synopsis methodica Li- 

 chenum," where that author, after speaking of the existence of this 

 envelope in Lichens, says, " Parmi les champignons c'est surtout 



* Vittadini's explanation of the formation of basidiospores would seem to 

 be intermediate between that of the MM. Tulasne and that of Schacht and 

 Hoffmann. According to Vittadini, the spore is formed within the ascus or basi- 

 dium, and is carried outwards by the protrusion of the inner membrane only of the 

 basidium. 



f With regard to the question as to whether the asci of Ascobolus are (as its name 

 would imply), really ejected, the authors say (note, p. 32), " Omnes apud Ascobolos quos 

 novimus, thecffi equidem supra discum hymeninum, singulse saltern sua vice debitoque 

 tempore, vertice emerso prominent et paraphyses plus minus excedunt, strato autem 

 supposito cui ab oiigine imponuntur semper quodam modo hserent, nee secus evacu- 

 antur atque Pczizanmi et cseterorum Discomycetum asci, nisi quod ita lailgo pr^re- 

 scindantur seu decaeuminentur, ut galericulus tintinnabuUformis amoveatur." Mons. 

 Coemans, in his recent able monograph of the genus Pilobolus in the " Memoires 

 couronnes," of the Belgian Academy, also expresses doubts as to the emission 

 of the asci in Ascobolus, a fact whicli, he says, has been rather assumed than 

 proved. 



