pet aa | Recent Literature. out 
in this connection as it does not seem to have ever been noticed in ‘The 
Auk’ is Reichert and Brown’s monograph ! on hemoglobin crystals in which 
the structure of these crystals in the blood of various birds as well as 
other vertebrates is discussed and its weight as a taxonomic character 
considered. 
Another work of the same class is Dr. Wood’s beautiful monograph on 
the eyes of birds which is now before us. This work deals mainly with the 
fundus oculi, or the back part of the eye, as viewed through the pupil by 
means of the ophthalmoscope, and presents in the main observations of 
the eyes of living birds, although studies have also been made of prepared 
specimens of birds’ eyes and of eyes of birds recently dead as well as micro- 
scopic studies of the tissues. 
The topics considered in the various chapters may be outlined as follows: 
A review of the anatomy and physiology of the organs and tissue seen in 
the fundus oculi; explanation of the ophthalmoscope and its use; study 
of the fundus of living birds through the ophthalmoscope,— the eye- 
ground, pecten, areas of acute vision, ete.; study of the fundus in prepared 
specimens; effect of domestication on the fundus oculi of wild birds; the 
appearance of the fundus in the various orders of birds; the ocular fundus 
in relation to a classification of birds; relation of reptilian to avian fundi. 
The work is illustrated by sixty-one beautifully prepared color plates from 
paintings by Mr. A. W. Head, of the fundi of various species of birds, as 
well as numerous outline cuts in the text. 
Birds according to Dr. Wood possess the most highly developed vision of 
any of the classes of vertebrates. They exhibit several different fovez or 
areas of acute vision, some concerned only with monocular vision, others 
with binocular. ‘‘Birds with double foveae”’, says Dr. Wood, “have 
exceptionally good eyesight with each eye separately; they are by this 
effective combination, enabled not only to command a view of the highest 
efficiency over the whole horizon, but also have the power to concentrate it 
when needed upon particular objects invisible or indistinctly visible to 
other species not so provided.’”’ But he adds ‘‘only when the histology, 
pathology, and experimental physiology of the avian cerebral organs and 
their connections have been worked out, as they have been in man, shall 
we know how the paths pursued by ‘brain currents’ involved in this 
switching from monocular single vision to binocular sight, run and are 
controlled.” 
Dr. Wood shows that there are six different arrangements of the areas of 
acute vision which seem to correspond quite closely with tle habits of the 
birds, the gallinaceous birds all coming under one head, the owls under 
another and the terns and swallows under a third. 
In the last chapters of the work he describes and figures in detail the 
structure of the fundus, the location of the areas of acute vision and the 
shape of the pecten, in a large number of species representing practically 
a Crystallography of Hemoglobins. Publ. 116, Carnegie Inst., Washington, D. C., 1909. 
