PLATE XIII. 



The lettering is the same in all the figures. 



Fig. 1. Transverse section through the mesoderm, ectodermal epithelium, and cuticle 

 of Scytophorus striatus. D, Oc. 2. 



Fig. 2. Longitudinal section through the pleated circular muscles of the wall at the 

 lower end of Halcampa clavus. A, Oc. 1. 



Fig. 3. Transverse section through the body of Scytophorus striatus passing through 

 the oesophagus, a 1 , Oc. 1. 



Fig. 4. Transverse section through the body of Halcampa clavus, passing through the 

 oesophagus, a 1 , Oc. 1. 



Fig. 5. Section parallel to the surface through the pedal disk of Halcampa clavus. 

 C, Oc. 1. 



Fig. 6. Transverse section through the pedal disk of Halcampa clavus. C, Oc. 1. 



Fig. 7. Half a transverse section through the lower extremity of Halcampa clams. 

 a 1 , Oc. 1. 



Fig. 8. Transverse section through the cuticle of Scytophorus striatus. D, Oc. 2. 



Fig. 9. Septum of the first order of Aatholoba reticulata; natural size. 



