27 
new case, becomes gradually obliterated. At last the upper 
extremity begins to develope shape (fig. 18), the ends of the 
new tube are displayed, the cilia at the mouth begin to play, 
and finally is reproduced a perfect copy of the original 
animal (fig. 1) in the enjoyment of independent existence 
and inhabiting a house of its own. In the course of time I 
presume this new creature will divide itself, and its compa- 
nion go through the same career, establishing itself in a new 
home. 
I have not been able to ascertain with satisfaction what 
becomes of the animalcule left in the tube after the migration 
of its companion — whether it goes on dividing itself again 
and again, whether it undergoes a change like its companion, 
or whether it gradually ceases to exist. The advanced 
season of the year is unfavorable for further observation at 
present. 
In numerous instances I have found the solitary Vagini- 
cola become filled with vacuoles, then subsequently with dark 
granules in active molecular motion, and which, after a time 
(while the animalcule is yet alive), are discharged in enor- 
mous quantity, and have the perfect appearance of Bacteria. 
The body then diminishes in size, becomes separated from 
attachment to the cell, and floats out a shapeless mass, and, 
to all appearance, quite destitute of life, but it does not 
dissolve away even after the lapse of several hours. 
Where specimens exist on Conferva numerous empty cells 
are found, therefore it may be safely inferred that the creature 
habitually, after a time abandons its cell. 
Monograph of Monera. By Ernst Hackel* 
With Plates IX & X. 
* [Note by Professor E. Perceval Wright, M.D., of 
Dublin. — Professor Haeckel’s ‘ Monographic der Moneren ’ 
appeared in the £ Jenaische Zeitschrift fur Medicin und 
Naturwissenschaft,’ band iv, heft 1, which was published 
on the 1st of May, 1868. Attention had been directed to 
this group by Haeckel in his ‘ Generelle Morpliologie,’ and 
again in his “ Natiirliche Schopfungsgeschichte.” The ap- 
pearance of this Monograph was, therefore, very welcome to 
all workers in this interesting field of research. I had at 
first intended, at the request of the Editors, printing in 
this Journal a resume of the principal facts detailed in this 
