CAUSE AND NATURE OF CROWN-GALL 00 



Several efforts were made to ascertain if the swarm-cells fused, 

 but these efforts were only partially successful. Fusing was 

 not observed with any of the swarm-cells arising from sowing 

 spores in hanging drops In one instance, however, several 

 amoeboid bodies 10 >>■ or more in diameter were found on the 

 slide, the material of which was obtained from a sporangium 

 that had ripened several days before and had been kept in a 

 moist cell in the meantime. On this slide were also found 

 large numbers of the pear-shaped swarm-cells provided with 

 the elongated cilium. 



GENERIC AND SPECIFIC DIAGNOSIS. 



It is evidently necessary to establish a new genus for this 

 slime-mold. The generic name which I propose is Dendroph- 

 agus, intended to suggest the cancerous character of the gall 

 tissue. The species may be appropriately named globusus, from 

 the form of the mature sporangium. 



Dendrophag-us, gen. now Plasmodium parasitic; sporangia 

 globose, sessile, simple ; peridial wall brittle, non-persistent, 

 shining, breaking in straight lines into small, irregular pieces ; 

 capillitium fragmentary, formed of a few irregular, branching 

 tubules attached to the lower portion of the peridial wall. 



D. globosus, sp. now Sporangia sessile, occurring singly or 

 in groups of two or three, i millimeter or less in diameter, 

 globular or slightly flattened and resting directly upon the 

 tissue of the host, deep orange, shining, opening irregularly ; 

 peridium thin, minutely granular when highly magnified, the 

 interior surface more or less covered with yellow protoplasmic 

 nodules of variable size and refractive power ; capillitium of a 

 few thick, blunt, sparingly branched, and irregularly nodular 

 hollow threads ; spores orange yellow, adhering in masses, 

 smooth, 1 1 4 to 3 ," in diameter. 



AFFINITIES. 



In its parasitic nature this organism resembles the Plasmo- 

 diophora. In all other respects it is allied to the true Myxogas- 



