Tl'.STACKLLA SCUTULUM, SOWKRr.V. 121 



to the sudden protrusion from the mouth, of the buccal cartilage, 

 which carries the radula or lingual ribbon. The protrusible organ 

 is milky-white, and the ribbon, studded with rows of barbed 

 chitinous " teeth," follows the general spoon-shape of the supporting 

 cartilage. As the latter becomes completely extended, the hollow 



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Tcstacella scutubtm, Sowerby — Buckhurst Hill, Essex. 



I I. The animal extended, seen from above. 



2. The same, but seen from the right side. 



3. The animal contracted, with the radula protruded. 

 30:. View of the radula from .above, enlarged. 



4. The same as figure 3, but the radula with an earthworm in its grip. 

 4a. Enlarged side view of the radula, as seen m figure 4. 



5. The animal enveloping the earthworm by gradual extension. 



6. Tooth, from the side of the radula. 



6a. The same, from a point nearer the centre of the radula. 

 ()b. The same, from very near the centre of the radula. 



