474 PROF. G, GULLIVER ON [June 15, 
prehensile claws, it would be impossible for them to mount trees 
without this special provision for climbling. 
In Tylonycteris and Glischropus the fleshy foot-pads without 
doubt perform similar functions, probably enabling these Bats to 
cling to the under surfaces of large leaves and fruits, perhaps not so 
effectively, however, as the much more highly specialized peduncu- 
lated sucking-disks of Thyroptera tricolor enable that animal to 
adhere to smooth surfaces.as securely as a fly. 
2. Observations on the Sizes and Shapes of the Red Corpuscles 
of the Blood of Vertebrates, with Drawings of them to 
a uniform Scale, and extended and revised Tables of 
Measurements. By Gurorce Gututver, F.R.S., late 
Professor of Comparative Anatomy and Physiology to 
the Royal College of Surgeons. 
[Received May 31, 1875.] 
(Plate LV.) 
No physiologist is likely at the present day to undervalue, as John 
Hunter did, the importance of the red blood-corpuscles. They often 
afford valuable characters which, though regularly ignored in the 
books of systematic zoology, should always form a part of the de- 
scriptions of the orders, and sometimes of the species, of each class 
of vertebrate animals. Higher still is the physiological significance 
of the corpuscles; their relations of individual size and of aggregate 
proportions to the other constituents of the blood, and to the eco- 
nomy of the species (in which we now kuow that the corpuscles per- 
form an important function intimately connected with their size and 
number), have become questions of much interest and moment which 
still require further investigation. 
But such inquiry would be foreign to the present purpose, which 
is to give simply the averages, with brief explanatory comments, of 
numberless measurements, all made by me, in the hope that they may 
be useful towards further researches of the same kind. And so many 
are the facts either suggested or shown by my Tables, in relation 
to the significance of the comparative sizes of the corpuscles, that I 
can here make no attempt to consider or develop this branch of the 
subject, It has been admirably treated by Professor Milne-Edwards 
in his ‘ Legons sur la Physiologie et l’ Anatomie Comparée,’ and was 
summarily noticed in my ‘ Lectures on the Blood, Lymph, and Chyle,’ 
delivered at the Royal College of Surgeons, and reported (with en- 
gravings) in the ‘ Medical Times and Gazette,’ 1862-3. On the 
taxonomic import of the nucleus of the red corpuscle, my observa- 
tions (illustrated by woodcuts drawn to a scale) are published in the 
‘ Proceedings’ of this Society (P. Z. S. 1862, p. 91, et 1870, p. 92) ; 
