()16 
F. H. EDGEWORTH. 
posterior digastric. The stylo-hyoid has lost relation with the 
posterior digastric ; it passes downwards, ending partially in 
a fascia lying at the posterior margin of the mylo-hyoid, par- 
tially by insertion into the hyoid. 
Eschweiler (1911), who did not refer to the papers of Futa- 
mura and Kallius, gave an account of the development of the 
stapedius in the pig. He stated that the Anlage of the muscle 
is first visible in embryos of 13 mm. Scheitel-Steissliinge,’^ 
and has no Abstammung von einer andern grossen Muskel- 
gruppe.’’ On the first development of ReicherFs cartilage the 
muscle enters into relationship with it ; it subsequently loses 
this and gains an attachment to the stapes. Der Mnsculus 
Stapedius ist ein echter Abkommling des Hyoidbogens und tritt 
erst sekundar mit dem Stapes, der dem periotischen Blastem 
enstammt, in Yerbindung.^^ The first basal attachment of 
the muscle is to the wall of the fossa stapedii s. Antrum 
petrosum laterale, and a certain rotation of the muscle takes 
place ‘An der Weise dass die Achse seiner Pyramide mit 
ihrem basale Ende nach hinten (aboralwarts) versclioben 
wird.” 
A re-investigation of the process of development in the pig 
showed the following : In a 13 mm. embryo there was no 
trace of an anterior digastric muscle. In a 14 mm. embryo it 
is being proliferated from the ventral surface of the hinder 
part of the intermandibularis, but is not separated from it, 
whilst the muscle Anlagen in the hyoid segment show the 
same structure as in the 15 mm. stage. In a 15 mm. embr\^o 
(figs. 55, 56) the anterior digastric is a little separated from 
the intermandibularis; it extends backwards and upwards on 
the lateral surface of the hyoid ventral constrictor portion of 
the muscle Anlagen in the hyoid segment, to about its middle. 
In the hyoid segment the hyoid bar consists of a continuous 
stapes, inter-hyale, and stylo-hyale (figs. 55-57) in a precarti- 
laginous condition, and the latero-hyale extends upwards from 
the junction of the inter-hyale and stylo-hyale towards the 
auditory capsule, which shows no trace of a fossa stapedii or 
crista parotica. The muscle- Anlagen (figs. 56-58), not yet 
