145 
cles which lie between the floor of the throat cavity and the ventral 
portion of the pharyngeus. The connection between the pharyngeus 
and the wall of the throat cavity is clearly indicated. Anteriorly of 
course the fore-end of the piston apparatus comes into view, and in 
front of this anularis musculature and lining of the funnel cavity 
have been cut through in the mid-dorsal line so exposing the cavity. 
The hyomandibulari-semianularis muscle (XXVJ) is a long slender 
muscle extending under the pharyngeus from its posterior attachment 
to the anterior region of the styloid process forwards to the hind 
lateral border of the anterior dorsal cartilage. The anterior half of 
the muscle consists of tendon. According to P. FÜRBRINGER, the function 
of this muscle is to draw back the anterior dorsal cartilage and there- 
fore the anular cartilage and upper border of the mouth, in order 
to accommodate the latter for fixation on a plane superficies. 
With one conspicuous exception I have now briefly and very 
imperfectly described in the case of Geotria australis most of the 
principal muscles mentioned by P. FÜüRBRINGER. The exception is the 
eye-muscles, to our knowledge of which my notes and sketches make 
no additions. 
The Superficial Nerves of the Side of the Head. 
Figure 30 shows the distribution of the facial nerves of Geotria 
australis seen on removal of the skin. I supply this figure because, 
apparently on account of the great development of the suctorial funnel 
and the gular sac, we have in Geotria two large facial nerves devel- 
oped which are absent or only slightly developed in other genera. 
Most dorsally there is a nerve (0.S.P.) which supplies neuromast 
organs on the dorsal side of the suctorial funnel and also the general 
skin of this region and therefore probably represents a combination 
of the Gnathostomatous nervus profundus, ophthalmicus superficialis 
and ophthalmicus trigeminus, and I find that Jonnston (22) states 
that this combination occurs also in Petromyzon. In Geotria this 
nerve arises, as in other vertebrates, from the side of the brain at 
the anterior end of the medulla oblongata and emerges on to the 
surface of the face just above the eye-ball. Emerging in front of and 
below the eye-ball there is another nerve (B.N.) which supplies 
neuromast organs in the region of the eye and possibly also the skin 
on the dorsal side of the funnel: this nerve probably represents in 
the main the nervus buccalis of Gnathostomes. JoHNnsTox figures the 
Anat. Anz. Bd. 45. Aufsätze. 10 
