A Monograph on the Sub-class Cirripedia Part 41

2. Mandibles of _Lithotrya dorsalis_, exhibiting four (_aa_) roughened, thin, ligamentous apodemes for the attachment of the muscles.

3. Mandibles of _Scalpellum Peronii_.

4. Mandibles of _Ibla c.u.mingii_.

5. Mandibles of _Lepas anatifera_.

6. Palpus of _Lepas anatifera_.

7. Palpus of _Pollicipes mitella_.

8. Palpus of _Alepas cornuta_.

9. Maxilla of _Lepas anatifera_.

10. Maxilla of _Lithotrya dorsalis_, exhibiting the h.o.r.n.y, rigid apodeme (_a_) buried in muscles, together with the two other princ.i.p.al bundles of muscles.

11. Maxilla of _Ibla c.u.mingii_.

12. Maxilla of _Lithotrya Rhodiopus_.

13. Maxilla of _Pollicipes polymerus_.

14. Maxilla of _Pollicipes mitella_.

15. Maxilla of _Poecilasma eburnea_.

16. Outer maxilla of _Conchoderma virgata_; (_a_), orifice of the olfactory cavity, the inner delicate chitine membrane of which is seen within, the specimen having been treated with caustic potash.

17. Outer maxilla of _Pollicipes mitella,_ showing the two princ.i.p.al muscles, and the prominent, tubular, (_b_) olfactory orifices.

18. Caudal appendages, and basal segments of the sixth pair of cirri, of _Lepas anatifera_; (_a_), a.n.u.s; (_b_), caudal appendages; (_c_), lower segment of pedicel of sixth cirrus; (_d_), upper segment of ditto; (_e_), basal segments of the two rami.

19. Caudal appendage (right-hand side) of _Pollicipes sertus_.

20. Caudal appendage (right-hand side) of _Scalpellum Peronii_.

21. Caudal appendage (right-hand side) of _Scalpellum vulgare_.

22. Caudal appendage (right-hand side) of _Pollicipes cornucopia_.

23. Caudal appendage (left-hand) _Lithotrya dorsalis_; (_a_), caudal appendage; (_c_), lower segment of pedicel of sixth cirrus; (_d_), upper segment of ditto; (_e_), segments of one of the rami.

24. Portion of caudal appendage of _Lithotrya dorsalis_, highly magnified.

25. _Pollicipes polymerus_; anterior ramus of the second cirrus.

26. _Lepas anatifera_; a segment of the sixth cirrus, showing the arrangement of the spines; (_a_), main anterior spines, of which there is a corresponding row on the opposite side; (_c_), dorsal tuft.

27. _Pollicipes polymerus_; a segment of the sixth cirrus, showing the arrangement of the spines; (_a_), main anterior spines, of which there is a corresponding row on the opposite side; (_b b_), calcareous s.h.i.+elds on the dorsal surfaces, with tufts of fine spines near their upper edges.

28. _Alepas cornuta_; sixth cirrus of; (_a_) basal portion of one ramus, consisting of numerous segments; (_k_), the other and almost rudimentary ramus.

29. _Poecilasma fissa_; segments of the sixth cirrus, showing the arrangement of the spines; (_a_), anterior spines; (_c_), dorsal tufts.