1026 
liver cells, but there is no answer to the mean- 
ing of the differences. 
The work as a whole is a valuable treasure- 
house of knowledge that will save both investi- 
gator and student much time and labor. The 
author does not state which system will form 
the subject of the next volume, nor when we 
may expect it to appear. At the same rapid 
rate of work it will be due in 1902, and we feel 
sure that the same excellence will be main- 
tained. 
B. F. KINGSBURY. 
RIVER PROFILES. 
AN interesting and valuable publication of 
the Department of Hydrography of the U.S. 
Geological Survey on the profiles of rivers in 
the United States, by Henry Gannett, has just 
been published and is now available for distri- 
bution. It embodies within a hundred pages 
the leading facts of about one hundred and 
fifty of the-most important rivers and streams 
of the country, noting their length, drainage 
area, the location of water power in their 
courses, their peculiarities of flow and the 
nature of their drainage basins. 
The rivers selected are those which are the 
largest in size and bear most directly upon the 
varied interests of the country such as the Con- 
necticut, Hudson, Susquehanna, Ohio, Poto- 
mac, Mississippi, Missouri, Platte, Colorado, 
Sacramento, Columbia and others. The figures 
for the table showing the height above sea- 
level and fall per mile were collected from 
various sources. Some were obtained from the 
report of the chief engineer of the U.S. Army, 
some from railroad companies when their lines 
cross the streams and some from the atlas sheets 
of the U. 8. Geological Survey. In the case of 
such rivers as the Connecticut, Susquehanna, 
Mississippi and Colorado, where the surround- 
ing country is in part or whole of peculiar 
physiographic interest, very excellent and vivid 
descriptions of its leading physical character- 
istics are given, which add to the interest, and 
render it valuable from an educational stand- 
point in geographic and physiographic instruc- 
tion. The pamphlet is the result of much 
careful work and is the first attempt to collect 
and compile this information in its present form. 
SCIENCE. 
[N. 8. Vou. XIII. No. 339. 
SOCIETIES AND ACADEMIES. 
ZOOLOGICAL CLUB, UNIVERSITY OF CHICAGO. 
WINTER QUARTER, 1901. 
1 
THE first meeting of the quarter on Jan. 9 
was devoted toa paper by Professor F. R. Lillie, 
entitled ‘A Comparison of the Power of Re- 
generation in Three Genera of Planarians, viz., 
Planaria, Phagocata and Dendrocelum.’ The 
following is an abstract of the paper: 
“The gréater part of the large volume of re- 
cent work on regeneration of planarians has 
been carried out on a single genus, Planaria. 
Attention should be called to the importance of 
the comparative method in studies of this kind. 
This may be illustrated by some results of 
observations on two other genera, Phagocata 
and Dendrocelum. These three genera are 
found living together in a single pond in Fal- 
mouth, Mass. Planaria is especially abun- 
dant in this pond, in some parts of which as 
many as twenty or thirty individuals may be 
found on the under surface of a single large 
stone. Scattered about among these individu- 
als one finds usually from one-half to one-third 
this number of individuals of Phagocata and 
two or three specimens of Dendrocewlum. 
Planaria is thus much more abundant than 
Phagocata and the latter than Dendrocelum. 
The last is more abundant relatively in por- 
tions of the pond where there is a large 
amount of vegetation growing on the bottom. 
The habits of life of the three genera in 
question are, however, very similar. 
‘¢ Phagocata was found to resemble Planaria 
very closely both in the modes of, and capacity 
for, regeneration. Dendrocelum, however, of- 
fers the greatest contrast to both Planaria and 
Phagocata. The first experiment was to cut a 
single specimen in half through the pharynx. 
The cut surfaces healed and the farther fate of 
the parts was as follows: The posterior part 
formed no new tissues, although it lived for 
some days ; from the anterior part, on the other 
hand, there grew out a pointed piece, which 
acquired the characters of a tail. Two weeks 
after the operation this piece also died without 
any extensive remodeling of the whole having 
taken place. I afterwards repeated the ex- 
