Figs. 1-7. — Suture-lines of Oxynotoids and a Deroceras. 



Ox. oxynotum. 



"W^ 



26 Ox. oxynotum (Am.cultellus) 



2 a Ox.oxynotum 

 (Am.cultellus) 



7. Deroceras bispinigerum x 3.5 



'^^/^ 



3. Ox.polyophyllum 



4. Gleviceras' glevense (genotype] 



6. Radstocklceras complicatum x 0.67 



5. Gleviceras glevense (Holotype) 

 [For fig. 7, see p. 302.] 



