84 EVOLUTION AND DISEASE. 
be found in other mammals, especially as the gill-slits are 
as marked in them asin the human species. The inquiry 
is full of interest. Our knowledge of branchial fistulz 
in mammals other than man is very scanty; this is 
not matter for surprise, as it is only of recent years 
that information regarding these fistula in him has 
been very exact or abundant. 
Fic. 42,—A Goat with cervical auricles. 
Heusinger? mentions the occurrence of congenital 
fistulae in the horse immediately below the ear, and 
near the angle of the jaw. He stated that they are 
more frequently recognized in carriage than in draught 
horses; the secretion or discharge which issues from 
* “Deutsche Zeitschrift fiir Thiermedicin,” Bd. ii. 
