42 
avoid omitting any data, it is well to rule the leaves of a good stout note- 
book before going to the field. The writer’s plan is to leave four lines 
across two opened pages for each specimen. On the left hand page rule 
vertical columns for: (1) Collector’s field number; (2) Locality; (3) Alti- 
tude; and (4) Date. On the right hand page rule vertical columns for: 
(5) Sex; (6) Name of species and common name, colour notes, habitat, 
etc., and (7) Measurements. 
The locality should be so indicated as to be intelligible to anyone 
with ordinary geographical knowledge, and should be stated with refer- 
ence to some definite, well-established geographical locality, province, ter- 
ritory, or district. In settled regions the county and the location in respect 
to nearest post office will do, but in unorganized territory, the locality 
should be connected with some officially named river, lake, or mountain, 
or, failing these, the latitude and longitude may be given. Names like 
“Goose lake,” and “Bear creek,” are so common that they mean little by 
themselves, and names like “Smith’s ranch” are transitory. If the region 
has high relief, altitudes should be given if possible, as different forms of 
life are found at different levels and the elevation may give the clue to the 
life zones. Altitudes may be obtained from maps, or in some cases from 
railway time-tables, and local heights may be estimated from the nearest 
known elevation. 
In writing dates, spell out the name or abbreviation of the months 
and do not express them by numbers. A common but reprehensible prac- 
tice is to write month-day-year, or day-month-year, in figures, but there 
is no uniformity about the custom, and one is left in doubt whether 3-2-32 
means March 2 or February 3. As it is confidently expected that many of 
the specimens are permanent enough to be extant more than 100 years 
from now, the year had also better be written in full. 
DETERMINING SEX OF MAMMALS 
The importance of carefully and unmistakably determining the sex 
of every mammal specimen and of marking the sex on the label can not 
be too strongly emphasized. In making scientific studies it is essential to 
be sure of the sex of specimens examined, as the presence or absence of 
primary and secondary sexual characters must be taken into account. 
Males and females frequently differ in colour and may moult or shed the 
coat at different seasons. The sexes usually show differences in dimen- 
sions of skull and bones, in total length of body, length of feet, and the 
differences often grow more pronounced as the animals grow older. In 
some of the less well-known species, these differences have not been well 
worked out, and it is important to have numbers of accurately sexed speci- 
mens to determine these differences. 
Some of the variations from the ordinary type of mammalian sex 
organs have been described in works on zoology and comparative anatomy, 
and an experienced anatomist can work out the exceptional cases by the 
light of reason. Unfortunately, the average field collector is not always 
deeply versed in anatomy, does not usually have the books at hand, and 
frequently does not know the name of the species which he may be working 
on. Mammal collectors of many years’ experience have been found groping 
in darkness while attempting to determine the sex of small mice or shrews 
and even of larger mammals. 
