OCCURRENCE, DISSEMINATION, MORPHOLOGY. 391 



form. Filamentous cells, measuring up to 40 yu in length and 2 fj. 

 in diameter, have been observed. Chains of elongated cells 

 frequently develop numerous rounded and oval cells on the ends 

 of the individual members (in giant colonies). 



As already mentioned, the appearance of this elongated cell 

 form is connected in part with certain conditions of environment, 

 so that, for example, the organism inside the nutrient liquid 

 produces mainly or entirely the more compact cell forms, whilst 

 the elongated forms are produced on the surface, as in the film 

 vegetations of Saccharomycetes. 



In giant colonies of many Torulacece, on the other hand, the 

 superficial cells are chiefly globular or oval, whilst the under side 

 exhibits numerous elongated, sausage-shaped cells, penetrating for 

 long distances into the gelatin. Other forms, again, develop both 

 within and upon the nutrient liquid, simultaneously with mixed 

 cells. 



The cell integument of Torulacece is of an even more highly 

 diversified character than in the case of the Saccharomycetes. It 

 is mostly strong, and in some cases of typical species attains a 

 considerable thickness that is apparently associated with strati- 

 fication. Still more frequent than in the Saccharomycetes (see 

 p. 145, vol. ii.) is the phenomenon of sloughing the outer layer of 

 skin. These extremely thick-skinned cells, which are found in 

 nearly all cultures, are possibly resting forms (Chlamydospores). 

 Conversely, the cell integument of many other Torula species is 

 very delicate. Sometimes, as in the species depicted by P. 

 LINDNER (XXXVII.), and the mucinous yeasts of MEISSNER (II.), 

 the cell wall develops an almost imperceptible mucous layer, 

 whilst in other species a gelatinous network is clearly visible (see 

 p. 178, vol ii.) in the film vegetations on nutrient liquids, and 

 occasionally the cultures transform the entire nutrient liquid into 

 a tough gelatinous mass. 



The cartilaginous film vegetations of certain close-growing 

 species on nutrient liquids may be attributed to a peculiar 

 condition of the cell integument. Species that, like Mycoderma 

 and Willia, produce superficial films very rapidly, imprison air 

 between the cells, a peculiarity favouring the assumption that the 

 cell integument is of a greasy nature, like that of Mycoderma. 

 No reports have been published dealing specially with the 

 chemical composition of the cell integument of Torulacece. 



Apart from isolated inclusions, the cell contents, as a rule, 

 have only slight refractive power and remain pale, agreeing in 

 this respect with Mycoderma and contrasting with the /Saccharo- 

 mycetes. While the cells are young, the contents are homogeneous, 

 but afterwards turn cloudy and frothy ; numerous small vacuoles 

 appear, to give place subsequently to a single one (in globular or 

 oval cells) or several (in elongated cells). The contents of older 

 cells are occasionally crumbly and finely granulated, or a number 



