164 LIVERPOOL BIOLOGICAL SOCIETY. 



S. 1. = Swift's 1 in. obj., oc. 2, magnifying about 45 diam. 

 q 1 — 1 230 



S.^= „ I „ „ „ „ 330 „ 



Z. j2- = -^^iss's ~ (oil immers.), oc. 2, ,, ,, 505 ,, 



Plate VI. 



Comparative views of the condition of the Epipodia as 



seen in transverse sections of various Opisthobranchiate 



Mollusca. 



Fig. 1. Sketch of Elys'ia from the dorsal surface to shov^ 

 the epipodia {e.p.) X 2. 



Fig. 2. Sketch of Aplysia from the left side to show the 

 epipodia (ep.), nat. size. 



Fig. 3. Outline of transverse section of Aplysia, one- third 

 along the body from the front, to show the 

 relations of the epipodia {e.p.), mantle (m) and 

 foot (/). Zeiss a*, 10. 



Fig. 4. T.S. (transverse section) of Acanthodoris pilosa, 

 through the rhinophores {rh.) showing the epi- 

 podial ridge and large papillae. S.l. reduced. 



Fig. 5. Another section of the same, about middle of 

 body, showing the distinctly lateral arrange- 

 ment of the papillae. S.l. reduced. 



Fig. 6. T.S. of Goniodoris nodosa, one-third along body 

 from the front (ten sections behind rhinophores), 

 to show the lateral epipodial ridges (e.p.). S.l. 



Fig. 7. T.S. of Polycera quadrUineata (60th sect, from 

 front) showing the lateral ridges at the sides of 

 the rhinophores. S.l. Compare with fig. 4. 



Fig. 8. Another of same (150th sect, from front, about 

 middle of body) showing the prominent ridges 

 (right side) and processes (left side) containing 

 glands, placed at the sides of the branchiae. S.l. 



