THE MANDIBULAR AND HYOID MUSCLES OF MA:HMALS. ()27 
})art of the inylo-hyoicl, wliilst in Cheiroptera and ^Iiistelida? 
some of the hinder bundles of the inylo-hyoid aiise from tlie 
liyoid. A representative of the ventral part of the liyoid 
constrictor is thus present, though not forming a stylo-hyoid 
muscle. 
In view of these phenomena of comparative anatomy and 
embryology it is probable that the accounts given by Ronviere 
and Futamura of the development of the stylo-hyoid of man — 
that it is an outgrowth of the posterior digastric — are in need 
of revision. 
On the Reported Instances of a iMonogastric Di- 
gastric ]\I n s c 1 e Inserted into the Lower Jaw. — 
Kohlbrugge found this condition present in one specimen of 
Hystrix with a fifth nerve innervation, and found a two- 
bellied condition in another specimen. The former was 
explained by Schulman as one in which an anterior digastric 
had extended backwards. 
In Manis javanica Kohlbrugge described the digastric as 
a simple muscle extending from the ^Miinteren Schadelseite 
zum Kieferwinkel/^ whilst in Manis macrura AVindle and 
Parsons found the digastric ^Onserted into the lower jaw as 
far as halfway to the symphysis.’^ In Manis pentadactyla 
(fig. 43) there is a muscle, with the insertion described by 
Windle and Parsons, arising partly from the mastoid and 
partly by fibres which are continuous with the platysma in 
the neck, i.e. an auriculo-mandibularis. The posterior 
digastric is present — in the form of a hyoid ventral constrictor, 
arising from the stylo-hyal and innervated by the X. facialis ; 
its anterior edge, ventrally, is continuous with the posterior 
edge of the intermandibularis. The anterior digastric muscle 
is absent. 
In Tatusia and Dasypus a monogastric muscle, attached 
below to the mandible, was described by Macalister, but later 
investigations by Toldt show that a posterior digastric passing 
to a ventral aponeurosis is present, so that the first described 
muscle is an auriculo-mandibularis. 
In Orycteropus, Humphry described the digastric as 
