Popoff, über das Vorhandensein von Tetradenchromosomen etc. 555 



In Hartmann's section on „Protozoology" in „Kisskalt and 

 Hartmann's Praktikum" (Jena 1907) some of Prowazek's figures 

 are rei^roduced and to some extent modified. For example, the' 

 two „reduction nuclei" (which Prowazek never shows clearly), are 

 figured quite unmistakably in fig. 8g (p. 117). And a very distinct 

 network is shown in the „sexual nuclei" in fig. 8 e — neither of 

 which is justified from Prowazek's publication. Further, Hart- 

 mann states that „Nach der Befruchtung kann direkt im gleichen 

 Wirt wieder das freie Flagellat aus der Cyste hervorgehen oder 

 aber die Cyste wird zu einer Dauercyste und dient der Neuinfektion" 

 (p. 117), I can find no statement by Prowazek to this effect. 

 Nor can I see how he could have made such an observation, since 

 all his description of the „autogamy" was based on stained pre- 

 parations, and not upon observation of the living animal. 



I think sufficient has now been said to show that autogamy 

 and chromidia are as yet unproven in the case of Bodo. My desire 

 in making the foregoing remarks has been to point out that too 

 much emphasis should not be laid upon this case — which is fre- 

 quently quoted in recent papers on the chromidia hypothesis — 

 before it receives ample confirmation. 



Explanation of Text-figures. 



(All figures are drawn from permanent preparations [fixed hot sublimate-alcohol, 



stained Heidenhain's iron-haematoxyliu], with the aid of a Leitz 2 mm oil-immer- 

 sion apochromat, with compensating ocular 12.) 



Fig. 1, a — 2). Various forms of cysts from the large intestine of the frog — arbi- 

 trarily arranged to show an „autogamy" similar to that described in Bodo 

 lacertae. 



Fig. 2. Four cysts from the frog's intestine — connected by remains of capsule. 



Fig. 3. A cyst from the intestine, showing darkly staining rodlike structures. 



Fig. 4, a and h, stages in the development of the cysts in the faeces. 



Fig. 5. Formation of buds by yeasts which have developed from the cysts. 



Fig. 6. A yeast forming a long outgrowth — from a hanging-drop slide culture 

 of the faeces. 



Fig. 7. Later stage of a similar form, showing segmentation into 4 cells. 



Über das Vorhandensein von Tetradenchromosomen 



in den Leberzellen von Paludina vivipara. 



Von Method! Popoff. 



(Aus dem zoologischen Institut in München.) Mit 6 Textfiguren. 



Die genaue Erforschung der Umänderungen, welche die Ge- 

 schlechtszellen in der letzten Periode ihrer Entwickelung durchmachen, 

 hat eine Fülle von komplizierten Wandlungen des Kernchromatins 

 dieser Zellen aufgedeckt. Die am Ende ihrer Vermehrungsperiode 

 angelangte Geschlechtszelle fängt allmählich zu wachsen an, und 

 durch das Leptotene-, Synapsis- und Pachytenestadium kommt sie 



