vegetates on the skin of the Gold-fish. 335 



nules about the 5000th to 6000th of an inch. Others again 

 contained no granular matter. These granules did not exhi- 

 bit molecular motion. I, on more than one occasion, observed 

 a steady onward motion of the granules and transparent ve- 

 sicle ; but this appeared to depend on unequal pressure and 

 level of the object plates. 



From certain spots on the external surface of the articula- 

 tions — spots which appeared to be arranged in no appreciable 

 order, there sprung bundles of very numerous, cylindrical, 

 elongated and transparent filaments. These were so nume- 

 rous and so convoluted and twisted as to defy every attempt 

 to disentangle them ; in fact, they occasionally obscured al- 

 together the stems or primary filaments of the plant. They 

 arose from all the articulations except the basal and terminal, 

 at least I never saw them springing from the latter, although 

 I occasionally saw them arising from what I took to be the 

 upper end of a basal articulation. They were quite cylindri- 

 cal, as thick at their free as at their attached extremities, and 

 about -^^-^--th. of an inch in diameter. In structure they were 

 homogeneous, apparently gelatinous, and covered with a fine 

 membrane. 



This parasite propagates by spores formed in its terminal 

 articulations, which become developed into spore-cases for 

 that purpose. Having observed terminal articulations in all 

 stages of development, I may state the changes they undergo 

 to be the following : — 



1. A perfectly barren terminal articulation is elongated, 

 spear-shaped, transparent, without granules. 



2. A terminal articulation which is destined to become a 

 spore-case does not elongate so much, and is from the first, 

 or at least from an early period of its growth, full of granules, 

 which give it a gray coloiu*. It is also elongated, fusiform, 

 and connected to the penultimate articulation by a narrow 

 neck. 



3. It becomes more distinctly fusiform, retaining its o^her 

 characters. 



4. The granules appear here and there to increase in size, 

 or at least larger granules appear diffused through the mass. 

 These larger granules or vesicles are more or less transparent. 

 The articulation now becomes cylindrical, with rounded ex- 

 tremities and a constricted neck. 



5. The articulation increasing in dimensions, but retaining 

 the same shape, contains a packed mass of perfectly trans- 

 parent globules, which are uncompressed and without appre- 

 ciable internal structure ^ 



6. The fertile articulation or spore-case bursts ; that is, I 



