20 W. A. HERDMAN. 



PLATE VI. 



FIG. 1. Leptoclin urn glariale, from a photograph ; x 2. 



Fro. 2. Coarsely granular cells from the test ; X 40. 



FIG. 3. Stellate spicules, from the test ; x 40. 



FIG. 4. Surface of an Ascidiozooid, showing branchial aperture and distribution of spicules. 



FifJ. 5. Stereodavella antardica, larger colony. 



FIG. fi. smaller colony. 



FIG. 7. Anterior part of an Ascidiozooid. 



FIG. 8. Amaroucium antarcticum, from a photograph. 



FIG. 9. Section of the colony. 



FIG. 10. Part of a section of the colony showing Ascidiozooids. 



FIG. 11. Ascidiozooid extracted from test. 



FIG. 12. Anterior end of Ascidiozooid enlarged. 



FIG. 13. Part of branchial sac. 



FIG. 14. Styela rotunda, from a photograph. 



FIG. 15. Part of branchial sac. 



FIG. 10. Part of surface of test, showing scales ; X 40. 



FIG. 17. Alimentary canal. 



FIG. 18.- Mantle ; X 40. 



FIG. 19. Dorsal tubercle. 



PLATE VII. 



FIG. 1. BoUenia scotti ; natural size. 



FIG. 2. Atrial aperture of same. 



FIG. 3. Another specimen with shorter stalk. 



FIG. 4. Atrial aperture of same magnified to show spines. 



FIG. 5. Smallest specimen of same. 



FIG. 6. Atrial aperture in profile to show spines. 



FIG. 7. Surface of test, magnified, showing three spines. 



FIG. 8. Two test spines in profile. 



FIG. 9. Dorsal tubercle of specimen shown in fig. 1. 



FIG. 10. Part of branchial sac and dorsal lamina of specimen shown in fig. 1. 



FIG. 11. Test in section, showing spines on surface. 



FIG. 12.- Unidentified Cynthiid (see p. 8). 



FIG. 13. One of the 4-lobed apertures of same. 



FIG. 14. Oihopleura gaussica, Lohrn., about natural size. 



FIG. 15. Tip of tail of same enlarged. 



FIG. 16. A, is, c, and D. Four sections through the tail of 0. gaussica to show different degrees of 



development of muscle bands above and below the notochord. 



FIG. 17. Magnified details of the wall of notochord, the muscle layer, etc., to show histological 



struct ore. 



