88 EVOLUTION AND DISEASE. 
may have a persistent branchial cleft, another have 
a cervical auricle only, and a third a persistent cleft 
and auricle. It is also a point of some interest to re- 
member that in the human subject the operculum of 
the third cleft is that most commonly seen in the adult. 
The pendulous bodies in the goat harmonize admir- 
ably with these conditions. Professor Charles Stewart 
detected in the auricle of the goat figured on page 84, 
an axial rod of coarse, yellow elastic cartilage, and 
Franck, in his work on the “ Anatomie der Hausthiere,” 
1883, states that in goats and pigs this rod of cartilage 
exists in these so-called bells (Glockchen oder Ber- 
locken), and draws attention to the existence also of 
striped muscle-fibre in them. The anatomy of a 
goat’s cervical auricle is shown in fig. 45. As these 
bodies occur in goats at the situation of the external 
orifice of the third branchial cleft, most anatomists 
are of opinion that they are homologous with the 
cervical auricles of man. 
An impartial consideration of the evidence relative 
to the development of the pinna in land mammals 
shows, clearly enough, that it is to be regarded as the 
confluent opercula of the first and second arch, extra- 
ordinarily developed from increased use in connection 
with the acoustic functions, which have gradually 
arisen in connection with the first branchial cleft. 
The remaining opercula have been suppressed partly 
from loss of function and partly from the excessive 
development of the first and second operculum. That 
the gradual development and increased importance of 
the external auditory apparatus is in a large measure, 
