THE SENSE ORGANS 149 
pure Negroes this cartilage was found by Giacomini in twelve 
individuals. 
The plica semilunaris varies greatly in size at different ages 
and in different races. In the new-born-child, and during the 
early years of life, it is broader than later, when it does not exceed 
14 to 2 mm. in breadth. One known exception to this rule 1s, 
however, found in the Malay tribe of the Orang-Sakai, in which it 
reaches a breadth of 5 to 54 mm. It would be worth while to 
examine other tribes in this respect. 
In the caruncula lachrymalis (c./., Fig. 91), which hes near the 
plica semilunaris, glands are to be found, which in their structure 
Fic, 92.—DIAGRAM TO ILLUSTRATE THE SHIFTING OF THE LACHRYMAL GLAND, 
WHICH HAS TAKEN PLACE IN THE COURSE OF PHLYOGENY. 
The gland shifts in the direction of the arrows ; a, its position in the Ampbibian ; 8, in 
Reptiles and Birds, and in certain human beings, in which case it may be regarded 
as atavistic ; c, normal position in Man. 
greatly resemble the lachrymal glands. These “ nictitating glands” 
constitute a distinct series and are in no way connected with the 
sweat and Mollerian glands (Peters). Further, sebaceous glands 
and fine hairs are, in the Primates, found near the caruncula. 
Finally, a mention may be made of accessory lachrymal glands 
which, with their ducts, occasionally lie near the conjunctival sac 
at the lateral angle of the eye (cf. Fig. 92)—i.e. in a position 
approximate to that of the lachrymal glands of Amphibia and 
Reptiles, and indicative of a gradual shifting of the lachrymal 
apparatus in the course of Phylogeny. 
Long stiff hairs which occasionally appear in the median 
