

12-f 



FIG. 203. View of Ciona intestinalis lying- on its right side. Both the branchial 

 aud the atrial cavities have been opened by longitudinal incisions. 



1. Mouth. 2. Tentacles. 3. Peripharyngeal groove. 4. Per- 



forated walls of branchial sac. 5. Endostyle, 6. Oesophageal 



opening leading from the branchial sac to the stomach, rather diagram- 

 matic. 7. Stomach. 8. Intestine showing typhlosole ; part of it removed 

 to show subjacent structures. 9. Kectum. 10. Anus. 11. Atrial 

 aperture. 12. Inner surface of mantle showing longitudinal and trans- 

 verse muscle fibres. 13. Dorsal tubercle. 14. Subneural gland and 

 brain. 15. Cut edge of branchial sac. 16. Heart. 17. Ovary. 

 18. Pore of vas deferens. The openings of the oviduct and the vas deferens 

 are shown enlarged to the right. 19. Testicular tubes on intestine. 



20. Oviduct. 21. Septum shutting off that part of the body-cavity 



which contains the heart, stomach and generative organs. 



