EXPLANATION OF PLATES. 137 



Fig. 5. Calcareous spicules from the test, highly magnified. 



Fig. 6. An Ascidiozooid, showing the course of the alimentary canal. 



Fig. 7. Muscle bundles in the mantle over the thorax. 



Fig. 8. Part of the branchial sac, from a section. 



PLATE Dm. II. 



Fig. 1. Leptoclinum incanum, n. sp. , several colonies, nat. size. 



Fig. 2. Calcareous spicules from the test, magnified. 



Fig. 3. Part of the surface, showing two common cloacal apertures. 



and a number of branchial apertures, enlarged with a lens. 

 Fig. 4. Part of the branchial sac, magnified. 

 Fig. 5. The alimentary canal. 

 Fig. 6. The anterior end of an Ascidiozooid in section showing tentacles, 



dorsal tubercle, dorsal languet, &c. , magnified. 

 Fig. 7. Leptoclinum patulum, n. sp. , colony, nat. size. 

 Fig. 8. Part of the surface showing the arrangement of the Ascidio- 



zooids, enlarged with lens. 

 Fig. 9. Arrangement of the spicules around the branchial aperture of 



an Ascidiozooid. 



Fig. 10. Small part of the branchial sac. 

 Fig. 11. Part of the test in section. 

 Fig. 12. The alimentary canal. 



PLATE PST. I. 



Fig. 1. Colony of Chorizocormus sydncyensis, Herdm., nat. size. 



Fig. 2. Part of test. 



Fig, 3. Part of branchial sac. 



Fig. 4. Part of branchial siphon, to show dorsal tubercle. 



Fig. 5. Alimentary canal. 



Fig. 6. Part of wall of intestine, showing digestive tubules. 



Fig. 7. Polycarps containing ova. 



Fig. 8. Colony of Chorizocormus snbfuscus, Herdm., nat. size. 



Fig. 9. Part of section of same, showing branchial sac, &c. 



Fig. 10. Branchial siphon from inside. 



Fig. 11. A polycarp containing ova. 



PLATE PST. II. 



Fig. 1. Colony of Chorizocormus Icucophaeus, Herdm., nat. size. 



Fig. 2. Part of mantle. 



Fig. 3. Part of branchial sac. 



