138 ALLEN’S NATURALIST’S LIBRARY. 
THE TAMARINS. GENUS mapas: Leon (oCee 
Midas, Geoffr., Ann. Mus., xix., p. 120 (1812). arel Lal ely 96 
This genus differs from the preceding only in the characters 
of some of the teeth. The canine teeth in the lower jaw are 
longer than their neighbouring incisors; but, as has been 
pointed out by Prof. St. George Mivart, it is a question whether 
this generic distinction can be maintained, as an intermediate 
condition exists in some forms. 
For the convenience of description the species of this genus 
have been divided into two groups—(a) those with long hair 
on the head and neck, and (0) those with short hairs on the 
back of the head. The number of species in the latter group 
is greater than in the former; and they are further divided 
into those with, and those without, white lips. 
I,J THE SILKY TAMARIN. MIDAS ROSALIA. 
Simta rosalia, Linn., Syst. Nat., 1., p. 41, pl. i. (1766). 
Midas rosalia, Geoffr., Ann. Mus., xix., p. 121 (1812). 
Leontopithecus rosalia, Gray, Cat. Monkeys Brit. Mus., p. 65 
(1870). 
Hapatle rosalia, Schl., Mus. Pays Bas, vii., p. 250 (1876). 
Characters.—This is the first species of the long-whiskered 
and maned group ; fur soft and silky ; tail equal in length to 
the body, bushy at the tip; hair round the face and on the 
back of the neck very long, forming a conspicuous ruff. Face, 
hands, and feet purple; general colour of the hair golden 
yellow, more or less red, and glossy. 
These animals are said to possess an air-sac in the throat, at 
the back of the ¢vachea (or windpipe), as in Azeles. Length, 
rr inches ; tail, 12 inches. 
