96 BULLETIN UNIVERSITY OF MONTANA 
Special Studies. 
Among the other groups special study was made on shells and dragon- 
flies. Shells in the State of Montana are relatively scarce. Few reports 
have been made on shells taken from this region. The only list so far 
available is the one given in Nautilus, Vol. VIII, p. 63, giving a list of 42 
species from the Missouri river. The material from the western side of 
the range lists 21 species. The conditions in the State of Montana are 
not favorable to the growth of shells. The rivers are rapid, with scarc~ 
ity of food, and with little lime. The lakes contain clear cold water, 
are usually deep, with few swampy places, and with rocky shores and 
bottoms. The marshy stagnant portions of the lakes are usually small, 
and liable to dry up in summer. The mountain sides in summer become 
dry and parched, except in protected portions and along streams. Great 
stretches of plain are without moisture for a portion of the year, and 
almost every living thing that cannot move to the water courses is killed. 
The days in summer are hot, the nights cool. The air is dry and evapor- 
ation is rapid. As a result of the above conditions we may expect great 
variation of species in adjacent regions, where the barriers may be sufii- 
cient to cut off all communication between the regions. It is hoped by 
making extensive collections of land and fresh water shells to secure 
sufficient material to throw some light on the geology of the region, which 
now offers many difficult and complex questions. One new species has 
been discovered, and the first living specimens secured. Another has 
been found at an altitude of 9,000 feet. In the report of the work on the 
lakes following information is given regarding the limited number of spe- 
cies found in each. 
The work on Odonata has been prosecuted with more or less vigor 
during the past four years, besides material taken at different portions 
previous to that time. The result is the discovery of about fifty species 
in the state, which is not a large showing. The same conditions making 
it difficult for shells to grow in the waters of the state will apply to drag- 
onflies. The young live in water, which must not be swift nor too 
clear, but must offer sufficient animal food to keep the larvae alive, must 
be stagnant enough to support life of such slow and uncouth water dwellers 
and must offer them suitable hiding places to keep out of the sight and 
reach of enemies. Such places are not common. In Illinois the writer was 
accustomed to visiting the ponds around town, taking as many as 25 spe- 
cies in a single afternoon. In Montana a hard and long day’s work has 
resulted in but six species, and not many specimens of these. From this 
it will be seen that dragonfiy collecting in the state is not only difficult, 
and the results meager in amount of material, but from what has been 
said there is a possibility of securing many new and interesting things. 
During the three seasons of collecting in the western part of the state 
large numbers of botanical specimens have been secured, which are de- 
posited in the herbarium of the University, and await study. 
It will now be helpful to the reader to give some information 
concerning the region under discussion, which will convey a better idea 
of the country than has heretofore been given. 
