CHIROPTERA 645 
the proximal extremity of the terminal phalanx of the fourth digit. 
The relative development of the digits and their phalanges will be 
noticed under each family. 
As might be expected from the small size of the posterior 
limbs, the pelvic girdle is relatively weak. The ilia are long and 
narrow. In the males of most species the pubic bones of opposite 
sides are very loosely united in front, while in females they are 
widely separated; and in the family [hinolophide alone do these 
bones form a symphysis. The ileo-pectineal eminence develops a 
long pectineal process, which in the subfamily Hipposiderine is con- 
tinued forwards to the anterior extremity of the ilium enclosing a 
preacetabular foramen unique among mammals. The acetabulum 
is small and directed outwards and slightly upwards; and with 
this is related the peculiar position of the hind limb already noticed 
as one of the chief characteristics of the order. The femur is 
slender and cylindrical, with a small head and very short neck, and 
scarcely differs in form throughout the order. The bones of the 
leg and foot are variable ; in the subfamily Molossine alone is there 
a well-developed fibula, while in all other species this bone is either 
very slender, or cartilaginous and ligamentous in its upper third, or 
reduced to a small bony process above the heel, as in Megaderma, 
or altogether absent, as in Nycteris. 
The foot consists of a very short tarsus, and of slender, later- 
ally compressed toes, with much curved claws. The hallux is 
composed of a metacarpal, a proximal and an ungual phalanx, and 
is slightly shorter than the other four toes, each of which has an 
additional phalanx, except in the subfamily Hipposiderine and in 
the anomalous genera Thyroptera and Jfyxopoda, where all the toes 
have the same number of phalanges as the first digit, and are equal 
to it in length. In the genus Chiromeles the first digit is thumb- 
like and separated from the others, and in the typical Molossinw 
the first and fifth digits are much thicker than the intermediate 
toes. 
The most noticeable peculiarities in the myology of the order 
consist in the separated bands or slips into which the platysma is 
divided, and in the presence of the remarkable muscle termed 
occipito-pollicalis, which extends from the occipital bone to the base 
of the terminal phalanx of the pollex. 
Although, as already mentioned, the brain presents a low type 
of organisation, yet probably no animals possess so delicate a sense of 
touch as the Chiroptera. It is undoubtedly this perceptive power 
which enabled the individuals deprived of sight, hearing, and smell, 
in Spallanzani’s well-known experiments, to avoid the numerous 
threads hung across the rooms in which they were permitted to fly 
about. In the common Bats the tactile organs evidently exist, not 
only in the delicate vibrissee which spring from the sides of the 
