112 HarozD HEATH, 
No. 9, 10, 11. The foregoing are all the muscles which attach 
to the radula and its supports but there are numerous others that 
undoubtedly operate in producing some of their movements. The 
most conspicuous of these are three great bands on each side that 
attach to the body wall and anteriorly unite with the pharynx and 
base of the semicircular groove. In Fig. 7 these are represented 
somewhat diagrammatically and appear to be parts of a single 
muscle but surface views show distinctly that such is not the case, 
The more dorsal muscle (9, Fig. 7) a short distance anterior to 
its origin on the body wall penetrates the space between Nos. 7 
and 8 and extending forward breaks up into a great number of 
lesser fibres that interlace most intricately on the forward wall of 
the pharynx and also attach to the wall bounding the semicircular 
groove.t) 
No. 10. The middle band also attaches to the body wall and 
passes almost horizontally forward to break up into a large number 
of subordinate bands that likewise surround the subradular portion 
of the pharynx or attach to the wall of the semicircular groove. 
No. 11. This muscle is considerably shorter than 9 or 10 but 
like them is attached to the body wall and on the other hand to 
the pharynx but in a more ventral position. Some of its fibres also 
pass to the body wall adjoining the semicircular groove. 
No 12. The anterior pharyngeal wall is also supplied with a 
pair of powerful muscles attached on the other hand to the body 
wall lateral to the section occupied by the salivary glands. Some 
of its more superficial ventral strands spread out over the subradular 
wall of the pharynx where they interlace with bands from 9, 10 
and 11. The greater number of the more deeply seated fibres attach 
to the anterior wall of the gut from the region held by the three 
foregoing muscles to the junction with the buccal tube, where certain 
of the bands unite with a few of the muscles (No. 13) encircling 
the buccal wall. 
No. 13. A strong circular band and two or three smaller ones 
surround the alimentary canal from the front of the pharynx to a 
1) For the sake of clearness a considerable space has been left in 
Fig. 7 between the pharyngeal wall and the semicircular groove, only a 
very few muscle bands traversing the cavity. In reality hundreds of fibres 
extending in all directions between these two points leave only a few 
minute passages through which the blood courses. 
