STRUCTURE. 57 



first under the form of a small rounded globule, and almost 

 entirely cellular. This small globule, the commencement 

 of the receptacle, is not long in increasing, preserving its 

 rounded form up to the development of the asci. At this 

 period, under the influence of the rapid growth of these organs, 

 it soon produces at its summit a fissure of the external mem- 

 brane, which becomes a more marked depression in the mar- 

 ginate species. The receptacle thus formed increases rapidly, 

 becomes plane, more convex, or more or less undulated at the 

 margin, if at all of large size. Fixed to the place where it is 

 generated by some more or less abundant mycelioid filaments, the 

 receptacle becomes somewhat cup-shaped and either stipitate or 

 sessile, composed of the receptacle proper and the hymenium. 



The receptacle proper comprehends the subhymenial tissue, 

 the parenchyma, and the external membrane. The subhymenial 



FIG. 33. Section of cup of Ascobolus. a. External cells. 6. Secondary layer, c. Sub- 

 hymenial tissue (Janczenski). 



tissue is composed of small compact cells, forming generally 

 a more coloured and dense stratum, the superior cells of which 

 give rise to the asci and paraphyses. The parenchyma is seated 

 beneath this, and is generally of interlaced filaments, of a looser 

 consistency than the preceding, united by intermediate cellules. 

 The external membrane, which envelopes the parenchyma, and 

 limits the hymenium, differs from the preceding by the cells 

 often being polyhedric, sometimes transverse, and united to- 

 gether, and sometimes separable. Externally it is sometimes 

 smooth, and sometimes granular or hairy. 



