138 EXPLANATION OF PLATES. 



Fig. 4. Branchial siphon from inside. 

 Fig. 5. Atrial siphon from inside. 

 Fig. 6. Alimentary canal. 



PLATE PST. III. 



Fig. 1. Part of a colony of Goodsiria lapidosa, Herdin. 



Fig. 2. Another colony of same. 



Fig. 3. Part of test, showing vessels, test cells, and imbedded foreign 



bodies. 



Fig. 4. Part of vessel from test. 



Fig. 5. Part of mantle. 



Fig. 6. Part of branchial sac. 



Fig. 7. Graphic formula of branchial sac. 



Fig. 8. Alimentary canal. 



Fig. 9. Digestive tubules from wall of intestine. 



Fig. 10. Tentacles and dorsal tubercle. 



Fig. 11. Part of polycarp, showing ova and sperm sacs together. 



Fig. 12. Group of sperm sacs and ducts, separated out. 



PLATE EOT. I. 



Fig. 1. Colony of Botnjlloidcs Icptum, n. sp., variety, nat. size. 



Fig. 2. Part of test of same, showing vessels and pigment cells. S. J. 



Fig. 3. Part of mantle, showing muscle fibres and pigment cells. S. \. 



Fig. 4. Part of branchial sac of same form. S. 1. 



Fig. 5. Colony of Botrylloides leptum, nat. size. 



Fig. 6. Part of very young Ascidiozooid occurring in a section and 



showing the ova, and the young longitudinal bars of the 



branchial sac. S. ^. 



Fig. 7. Section of the edge of the test. S. . 

 Fig. 8. Section of another part of the test. S. J. 

 Fig. 9. Ventral edge of branchial sac, showing endostyle. 

 Fig. 10. Another part of branchial sac, near dorsal lamina. 

 Fig. 11. Alimentary canal of same species. 

 Fig. 12. Branchial siphon from the inside, showing the 4 large and 



4 small tentacles and the dorsal tubercle, &c. S. -. 

 Fig. 13. Longitudinal section through stomach showing the folds. S. %. 



PLATE BOT. II. 



Fig. 1. Colony of Sarcobotrylloides jacksonianum, n. sp. 

 Fig. 2. A common cloacal aperture from same colony. S. ^. 

 Fig. 3. Section of test. 



