XXill 
after the occurrence of the storm, and, having already parted with a great 
many specimens, he would not allow me to take one away with me for 
closer examination at home. But I saw enough to satisfy me as to their 
nature, if not to identify the exact species. They were not, as may be 
supposed, true insects, nor were they Entomostraca, as Professor Westwood 
thought they might perhaps have been, but forms of Infusoria, more 
especially of the genus Vibrio, large numbers of which were present, some 
swimming freely in the water, but the greater part congregated in spherical 
masses about the size of a small marble, each mass being surrounded 
by a semitransparent filmy sort of skin or envelope, through which the 
minute worms might be readily discerned with a pocket lens, tangled 
together and in a nearly quiescent state. I believe them to have been the 
Vibrio undula of Miiller (‘Animalcula Infusoria,’ p. 46, tab. vi. figs. 
4—6, 1785), or some very closely-allied species; and his figure gives an 
exact representation of the appearance of the congregated masses of worms 
as presented in this instance, this habit being characteristic of the species. 
He speaks of the masses being sometimes collected round the branchlets of 
a conferva (as given in one of his figures). The surrounding skin, which - 
I have alluded to above, I suspect to have been nothing more than a pellicle 
of scum, &c., deposited from stagnant water, perhaps rendered thick by 
evaporation. I was told there had been a sudden squall of wind before there 
came on a heavy rain, and my idea is that these organisms must have been 
lifted up by the force of the wind, acting in a gyratory manner, from some 
shallow pool in the neighbourhood, reduced perhaps to little more than 
a large puddle, in the centre of which, from the drying up of the water 
around, the organisms had collected. A boy at the station first noticed 
them (i.e. the above spherical masses) falling on his coat, &c., as the rain 
came on, and shortly after, as the rain fell more heavily, the platform, so 
much as was not under shelter,—so I was told,—was covered with them. 
A few had been observed during a storm some days previous to the fall of 
of which the above is an account.” 
Mr. Butler exhibited species of Lepidoptera, upon which experiments had 
been made by Mr. Meldola, with regard to testing the effects of dyes. The 
insects were Pieris brassicee and napi, Gonepteryx rhamni, Vanessa urtice, 
Pyrameis Atalanta and Arctia caja. The most striking effects were ob- 
servable in P. napi dyed black, and A. caja dyed metallic-green and magenta. 
The dyes used were aniline. Mr. Meldola dissolved the dyes in spirits of 
wine and laid them on with a camel-hair pencil. Not being satisfied with 
Mr. Meldola’s experiments, Mr. Butler resolved upon performing others on 
his own account; but being then ignorant of the system pursued, he dis- 
solved his dyes in hot water, and discovered that the specimens would not 
take them. He then made a solution of soda, into which he dipped 
G. rhamni, and found that the yellow pigment immediately united with the 
