422 C. CLIFFORD DOBELL. 



filament. This condition may be more or less strongly- 

 marked : it may take the form of a simple bend, or it may 

 take the form of a spiral filament consisting of one or more 

 turns (see fig. 52). 



It might be urged that the bilobed cells wliicli contain 

 a zig-zag, bent, or spiral filament are really different organisms 

 from those under consideration. The proof that this is not 

 the case lies in the fact that all stages can be found together 

 in the same chain of organisms (fig. 52). There can be very 

 little doubt that these chains are formed from the successive 

 divisions of an originally single Micrococcus, In the short 

 chain depicted in fig. 52, a pair of such forms is seen at the 

 lower end of the chain. Above these, four dividing cocci are 

 seen Avhich show various modifications of the dividing 

 nucleus, from a slightly distorted dumb-bell figure to a 

 zio--za"" or spirtil filament. 



I regard this configuration of the nucleus as of considerable 

 sio-nificance. The matter will be discussed at greater length 

 in a subsequent section of the paper (see p. 471). 



Cocco-bacillar Forms from Lacerta muralis. 



Now in addition to the coccus forms which I have just 

 described, there are many organisms which cannot be very 

 •definitely classified with either coccus forms or bacillar forms, 

 but which occupy an intermediate position. These forms 

 (fig. 50) present the appearance of a slightly elongated sphere, 

 or of a very short rod with rounded ends. The shortest, most 

 spherical forms (fig. 50, upper right-hnnd individual) have a 

 nucleus which is in the form of a short and usually bent 

 i-odlet. The longest forms (hg. 50, lower and upper left- 

 hand individuals) show a nucleus which is in the form of a 

 filament arranged in a more or less zig-zag or spiral manner. 

 That such organisms are in a "resting" (i.e. not dividing) 

 state, appears certain fi'om the fact that no cytoplasmic 

 constriction can be seen (compare figs. 45-50 and 52). 



As I have already noted, the ordinary Micrococcus 



