242 
JOURNAL OF MAMMALOGY 
and taxonomic relationships of the principal groups of marsupials accompanies 
the discussion. 
The essential points in Doctor Osgood’s carefully prepared summary of his 
studies of CcBnolestes, briefly stated, are: 1. CoBnolestes is a surviving member 
of an ancient group and retains many primitive characters. 2. It has numerous 
resemblances to modern peramelids. 3. It has few non-marsupial characters and 
no great degree of specialization. 4. It has no especial affinity to the American 
Didelphiidse. 5. The ancestor of the caenolestids was probably a northern form 
which had already separated from the generalized polyprotodont stock. 6. The 
North American ancestor of the caenolestids possibly extended throughout 
Holarctica and therefore may also have given rise to the Australian diprotodonts. 
7. The phylogenetic and morphological relations of Ccenolestes are best ex- 
pressed by classifying it in the suborder Diprotodontia, family Palaeothentidae, 
subfamily Caenolestinae. 
The text closes with six pages on the brain of Ccsnolestes ohscurus, by Dr. C. 
Judson Herrick, professor of neurology. University of Chicago. The figures in 
the plates are well executed (the line drawings of muscles and soft parts are 
credited to R. E. Snodgrass, a sufficient guarantee of accuracy), and each plate 
is faced by a lettered reference page so that, in using the work, it is unnecessary 
to search constantly for a special “explanation of plates.” There is, unfortu- 
nately, no index. 
— N. Hollister. 
King, Helen Dean. A Comparative Study of the Birth Mortality in 
THE Albino Rat and in Man. Anat. Record, vol. 20, pp. 321-354. March 
20, 1921. 
A summary of the results of Doctor King’s valuable experiments shows that 
during a period of 5 years in a total of 31,670 newborn albino rats 415, or 1.3 per 
cent, were stillborn- Under normal environmental conditions not more than 
2 per cent of rat fetuses are dead at birth. Normal birth mortality in man is 
about 4 per cent. There are no data regarding percentage of stillbirths in other 
mammals. The normal sex ratio in newborn albino rats, including stillborn, 
is about 107 males to 100 females. The average in man is about 108 males to 100 
females. Doctor King found an excess of males among stillborn in rats, the 
ratio being 129.3 males to 100 females. Sex ratio among stillborn children is 
about 130 to 140 boys to 100 girls. In the rat the percentage of stillbirths seems 
to vary somewhat with the seasons, being greatest in the autumn and least in 
the spring. It appears that malnutrition is directly responsible for most of the 
stillbirths. 
— Hartley H. T. Jackson. 
Johnston, T. B. The Ileo-caecal Region of Callicebus personates, 
WITH SOME Observations on the Morphology of the Mammalian Caecum. 
Journ. Anat. (London), vol. 54, part I, pp. 66-78. 1919. 
These studies are based chiefly on the Brazilian mammals Callicebus personatus, 
Dasypus sexcinctits, Tatusia novew.cincta, and Cyclothurus didactylus. In CaU 
licebus the caecum is an actively functioning part of the alimentary canal. The 
paired lateral caeca of Dasypus sextinctus and D. villosus are regarded as the 
