30 
NOTES AND MEMORANDA. 
ance of an animal figured and described by Pritcbard as a young 
Stepbanoceros, a dark globular mass witb five spreading or divergent 
tentacles, and at tbe distal extremity a very sligbt prolongation by 
wbicb it was attached to a plant-stem by an almost invisible thread, 
devoid entirely of any cell or carapace. Not long, however, was it 
destined to remain in this nude condition, for in twenty-four hours 
appearances of a cell were visible, and within three days it was 
domiciled in as beautiful a spiral case as the one it had left. Its 
contractile muscle developing rapidly with the length of the cell, in a 
few days it presented to the observer all the peculiarities of the 
parent, and within two weeks was again ready for another change such 
as is above described, and which was accomplished with a similar 
result. The Stepbanoceros being too high in the scale of animal life 
to propagate by gemmation or division, the process above portrayed 
can have but a remote influence upon reproduction, as there was no 
multiplication by this change. 
The original cell with its retracted body within, though remaining 
for weeks in an apparently perfect condition, was not seen to increase 
or in the least to change — the growth-force seemingly being confined 
to the detached head and its accompanying organs. 
Dr. Leidy stated that he had never seen specimens of Stepbano- 
ceros until they were shown to him by Mr. Peirce. 
NOTES AND MEMOEANDA. 
Wenham's Reflex Illuminator, — Mr. Samuel Wells writes as 
follows to the ' Boston Journal of Chemistry ' (June, 1875) : — Last 
September I received this ingenious illuminator from London, and 
examined several slides with its aid. The beautiful effect of a bright 
and clear illiunination of the object, shown on a dark background, as 
described by the inventor and by Mr. Slack, was very interesting and 
instructive. I had then but few slides on which I could use it, and 
laid it aside for further investigation at a future time. 
Mr. Wenham describes it in the 'Monthly Microscopical Journal,' 
vol. vii.,p. 236. It was designed for the illumination of such objects, 
mounted dry, as adhere to the -Burface of the slide, by rays of light of 
such obliquity that they cannot be transmitted beyond that point. 
The illuminator being connected with the slide by a film of water, 
the light passes through to the upper surface of the slide, and, if there 
is no object in contact with the slide at that point, is totally reflected ; 
if, however, a diatom or other object rests on the slide at the point 
where the light strikes, the rays enter the object and are diffused by 
it so that it becomes in effect self-luminous. 
This appears to be the only use for the illuminator described by 
the inventor. I have, however, lately used it for a different purpose. 
