(124 



Plate IV. 



ACLESIA CIUKHIFEllA, Q. ct G. 

 FIG. 



1. Upper margin of the gill (rhachis). 



2. a, Hermaphrodite duct ; b, anterior genital mass ; c, spermatocysta 



d, sperm-oviduct ; e, spermatotheca ; f, vulva. 



3. From the interior part of the rasp. 



4. One of the plates. 



(Figs. 3-4 with Cam. '200 x .) 



5. Lateral plate. 



6. Lateral plate. 



7. Three outermost plates. 



(Figs. 5-7 drawn by Gam. 350 x .) 



Pleurobkaxch.i:a capensis, B. 



8. Piece of the mandible, from the side. 

 0. Piece from the surface. 



(Figs. 8-9 with Cam. 350 x .) 

 10 and 11. Plates of the rasp in different positions. 200 x . 



PlEUKOBEANCH.KA MELANOI'US, B. 



12. Elements of the mandible, from the side. 200 x . 



13. Piece of the mandible, from the surface. 



14 and 15. Plates of the rasp, in different positions. 

 (Figs. 13-15 by Cam. 350 x .) 



0SC.\NI0PS1S PLEUKOBKANCH.EANA, B. 



16. Part of the frontal margin. 



17. Part of the mandibles. 350 x . 

 18 and 19. Largest plates of the rasp. 



20. Outer end of a series of plates, a, outermost. 



(Figs. 18-20 with Cam. 200 x .) 



21. Salivary glands with ducts. 



Oscanieela NiGROPUNCT.vrA, B. var. 



22. Element of the mandible. 



23. Innermost plates. 



24. Plates from the inner half of the rasp. 



25. Plates from the outer half of the rasp. 



26. Outer part of a series of plates, a, outermost. 



(Figs. 22-26 drawn by Cam. 350 x .) 



Berthella granulata, Krauss. 



27. Shell from the upper side. 5/1. 



28. Piece of mandible. 350 x . 



