The Morphology of a Solenogastre. fatal 
of the radula supports. In early life this muscle is probably 
distinctly paired for in adult specimens a delicate connective tissue 
septum along the mid line divides it for some distance anteriorly. 
No. 2. Another pair of muscles (tooth abductors), each of not 
more than one fourth the size of the foregoing (Fig. 15), are also 
attached to the bottom of the epithelial fold between the front ends 
of the supports but anterior to the insertion of No.1. A considerable 
number of its fibres also attach to the epithelium immediately 
beneath the first five or six teeth of each row. All these minor 
bands pass round the outside of each radular support to which they 
attach about half way back after having spread out, fan-like, to a 
considerable degree. 
No. 3. Immediately in front of the first pair of teeth a small 
muscle unites the extreme anterior tips of the radular supports (Fig. 4). 
No. 4. The supports are also united by an extensive yet 
relatively thin sheet of muscle which binds together the dorsal 
borders throughout their middle portion (Fig. 16). 
No. 5. Two small muscles attach to the latero-dorsal wall of 
the radula sac immediately in front of the point where this commences 
to open into the pharynx. More posteriorly the fibres from each 
side unite on the dorsal side of the sac where they are attached 
immediately in front of the insertion of the radula protractors (Fig. 7, 8). 
No. 6. Between the insertion of the radula protractors and the 
foregoing muscle, and apparently blending with them are several 
small longitudinal fibres immediately ventral to the digestive tract 
(219.55). 
No. 7, 8. Up to the present time the muscles considered are 
chiefly concerned, as we shall see, with movements of the teeth 
and do not take part in the greater motions of the radula as a 
whole and of its supports. These are produced by several highly 
developed muscles among which are the two pairs of radula 
protractors (Fig. 7). The more dorsal pair attaches to the sides of 
the radula sac not far from its posterior end and a very few of 
its fibres in most if not all cases also unite with the ventral 
oesophageal wall. Passing outward and forward as a fan-shaped 
band it attaches to the body wall. 
The ventral pair (8) attaches to the ventral side of the radula 
sac in the same section as that occupied by No. 7. It also passes 
forward parallel with the foregoing muscle and attaches to the 
body wall. 
