702 ALLIS. Vion. sxaily 
rior face of the clavicle. In the skin on the outer surface of 
the muscle, opposite the posterior septum, the anterior end of 
the posterior flagellum (//%) has its attachment. No special 
attachment to the clavicle, such as Sagemehl describes (No. 106, 
p. 63), could be found, nor were there what could be called 
special muscles connected with it. Certain fibres of the sterno- 
hyoideus were, however, inserted on the inner surface of its 
anterior end, or base, as McMutrrich has described. The ante- 
rior flagellum (//a) is attached to the skin alone, a little in 
front of the anterior septum. 
The trunk muscles, although projecting, internal to the 
clavicle, slightly beyond the inner, curved edge of that bone 
immediately above the sternohyoideus, are in no place con- 
tinuous with that muscle. No indication was found of a sepa- 
ration of the sternohyoideus into a hyodorsalis and hyoventralis, 
such as Schneider describes in Esox (No. III, p. 116). 
The sternohyoideus is innervated by the united ventral 
branches of the first three occipital nerves, and by the ventral 
branch of the fourth occipital nerve, or by a branch of that 
branch. The branch of the fourth occipital nerve innervates 
the posterior segment of the muscle, the first three nerves in- 
nervate the two anterior segments, a terminal branch of these 
united nerves being sent to the branchiomandibularis as already 
stated. 
The muscles of the pectoral fin are innervated by branches of 
the ventral branches of the first six spinal nerves, and, in the 
two dissections made, by a corresponding branch also of the 
ventral branch of the last, or fourth, occipital nerve. 
3. Occipital Region of the Skull. 
The occipital region of the skull, in the adult of the lower 
vertebrates, and of the head, in their embryos, is not defined 
and limited in the same way by different authors. Gegenbaur 
(quoted No. 104, p. 189) defines it, definitely, in adult sela- 
chians, as that part of the skull that lies posterior to the vagus 
foramen; and Froriep (No. 34, p. 226), in chick embryos, 
as that part of the vertebral column that is included between 

