266 NOTE BY PROFESSOR E. RAY LANKESTER. 



And again as alternatives — 



S. Plastids homogeneous (no cell wall distinguishable from 

 contents) ; or, 



4. Plastids lociilate (unilocular or moltilocular). 



Under heading c we have the colouring matter — 



1. Diffuse ; or, 



2. Locular (confined to the substance within the loculi). 

 Lastly, under heading d we have as varieties in the mode of 



aggregation of the plastids the following, which undoubtedly 

 is not an exhaustive list : — 1. Linear (thread-like) ; 2. Stellar ; 

 o. Globose ; 4. Massive ; 5. Arborescent ; 6. Catenular ; 7. 

 Reticular; 8. Tesselate. 



Dr. Klein's new form of Bacillus anthracis consists of 

 plastids of spherical shape, and each plastid is unilocular 

 and clean; the plastids are in catenular aggregation. But 

 a special kind of catenular aggregation is exhibited by Dr. 

 Klein's growth, inasmuch as there is an irregularity in the 

 size of the aggregated spherical plastids. At approximately 

 regular recurrent intervals large spherical plastids are inter- 

 posed between series of smaller ones. Such an arrangement 

 of spherical plastids aggregated in chains is familiar to botanists 

 in the case of the Alga Nostoc, and hence this variety of ca- 

 tenular aggregation in the Bacteriacese may be conveniently 

 registered as " nostocoid catenular aggregation." 



The commonly known twisted filaments obtained in culti- 

 vations of Bacillus anthracis, and figured in fig. 4 a of 

 Dr. Klein's plate, are linear aggregates of very short 

 bacillar plastids. It will be found most convenient to sepa- 

 rate these very short cylindrical plastids from the longer 

 forms (twice or many times as long as they are broad) under 

 the name ^'micro-bacilli'^ — the longer cylindrical plastids, 

 such as are commonly observed in early stages of a growth of 

 Bacillus subtilis, being called "bacilli" as heretofore. 

 Short rods built up by linear aggregation of micro-bacilli arc 

 not to be confused with homogeneous macro-bacilli consisting 

 of one elongated plastid. The twisting of the linear aggre- 

 gates into a rope, shown in fig. 4 a, introduces to us the 



