CROCKER LAND EXPEDITION 
some they may be said to be linked and they 
give departures from the Mendelian ratios.” 
Inasmuch as factors which usually le in 
different chromosomes may sometimes come 
to lie in the same chromosome, Morgan has 
suggested that when the maternal and pater- 
nal chromosomes pair in the maturation 
stages of the egg or spermatozo6n, the chro- 
mosomes of each pair may actually fuse at 
certain pots where they cross each other 
and thus portions of the chromosomes with 
their factors exchange places. With this 
interesting hypothesis as a basis he has been 
able by means of his breeding experiments 
with fruit flies to plot the location of particu- 
lar inheritance factors in individual chro- 
mosomes. This work, although in many re- 
spects hypothetical, is well supported by 
evidence and it is probably the most impor- 
tant work ever done on the ‘‘architecture of 
the germ-plasm.” 
A large number of cases are presented in 
which the sexes differ in color, form or habit 
and the inadequacy of Darwin’s theory of 
sexual selection to account for these second- 
ary sexual characters is generally admitted. 
Similarly it is shown that the selection of 
continuous variations, or of what might 
better be called non-inherited variations, is 
of no evolutionary significance. Even in 
the case of discontinuous or hereditary 
variations the author shows that natural 
selection plays no part in the formation of 
these variations. 
The effects on secondary sexual characters 
195 
of the removal and of the transplantation of 
ovaries or testes are described in the fifth 
chapter and the conclusion is reached that 
“the secondary sexual characters in four 
great groups, viz., mammals, birds, crustacea 
and insects are not on the same footing.”’ 
Those interesting cases in which both sexes 
are united in the same individual or in which 
eggs develop without being fertilized are 
treated at some length in the sixth chapter, 
and here as everywhere else Morgan draws 
to a large extent upon his own researches. 
In the chapter on fertility and sterility 
many scattered and diverse observations are 
summarized, though the facts cannot at 
present be satisfactorily generalized or ex- 
plained. The last chapter deals with special 
cases of sex-inheritance, such as sex in bees, 
peculiar forms of sex-linked inheritance in 
fruit flies, and the sex ratios in birds, frogs 
and man. 
This book was written on the firimg lines, 
as it were, of biological science and it deals 
with many matters which are not finally 
settled. It is inevitable that such a book 
should encounter differences of opinion on 
the part of other investigators in this field, 
but the author is peculiarly happy in his 
manner of presentation. He writes as one 
who is convinced and yet tolerant and open- 
minded. His style is brief, keen, attractive, 
and best of all in a scientific work he shows a 
thorough, first-hand acquaintance with the 
phenomena described, and sound judgment 
and good imagination in dealing with them. 
NOTE ON THE CROCKER LAND EXPEDITION SHIP 
By George H. Sherwood 
Acting Chairman of the Committee in Charge 
HE Committee in Charge of the 
Crocker Land Expedition announces 
that it has chartered the ‘George 
B. Cluett”’ for the purpose of trans- 
porting to New York the members of the ex- 
pedition party which went north in 1913 on 
the chartered ship ‘Diana.’ The ‘‘Cluett”’ 
is a three masted auxiliary schooner owned by 
the Grenfell Association and used by it for 
carrying hospital and food supplies from St. 
Johns, Newfoundland, to the various mission 
stations along the coast of Labrador. The 
“‘Cluett”’ was launched on July 1, 1911, and 
is one hundred and thirty-five feet over all. 
She is well built and heavily timbered and 
is to be “fortified”? as a further protection 
against the ice before starting on her journey 
northward. 
The “Cluett’’ will leave Battle Harbor 
about the first week in July, go directly to 
Etah, there taking on board the members of 
the expedition party, their collections and 
equipment, and willreturn to New York some 
time during September. Captain George 
Comer of East Haddam, Connecticut, hasbeen 
engaged by the Committee to serve as ice 
