REVIEWS AND BOOK NOTICES. 289 
mon base of the flagello, and in every instance observed, the 
act of ingestion was preceded by a quick bending of the larger 
_ flagellum by which the particle of indigo was thrown against 
the surface of the body in a manner similar to that described 
by Professor Clark in his observations upon Monas. So far as 
I was able to follow the process, whenever a colony reduced its rate 
of motion sufficiently to permit of careful observation upon this 
point, it was so much like the process described in Monas as to 
leave little doubt in my mind that it was substantially Fig. 92. 
the same: although as I have said I did not see a dis- 
tinct mouth. 
It appears probable, now that the Monadina are bet- 
ter understood, that we shall soon be able to recognize 
in them a well-defined family of the Flagellate Infusoria, oe 
although doubtless many forms that have been assigned Monad. 
to that group are vegetable in their nature; these will be gradu- 
ally removed and those forms which are unquestionably animal 
will be distinguished: among these it seems to me the genus 
Urella as described by Ehrenberg will undoubtedly take its place. 
Figure 88 represents a colony of about forty monads; Fig. 89 
an ideal section through such a colony ; Fig. 90 represents a group 
of five; Fig. 91 of two, and Fig. 92 a single monad. I have at- 
tempted to sketch in this last the position of the large flagellum 
when throwing a particle of food against the mouth region. 
All the above figures are enlarged one thousand diameters. 
REVIEWS AND BOOK NOTICES. 
GEOLOGICAL Survey OF On10.*— Though this is but a yearly 
report of progress, yet itis an important contribution to American 
geology, both in its purely scientific and practical aspects. We 
are convinced that when the final reports shall be published, the 
Citizens of the State of Ohio will feel proud of the thorough and 
able manner in which the survey has been carried on and com- 
Borys ee E ee AN 
*Report o Pipe 1870. By J. S. Newberry, Chief Geologist. Including 
Reports by E. B. peatentiag Edward Orton, J. H. Klippart, piron Geologists; T.G. 
Wormley, Chemist; G. K. Gilbert, M. C. Read, W. B. Potter and Henry Newton, Local 
Assistants. Svo, pp - 568, with maps and engravings. 
AMER. fi sah VOL. VI. 19 
