594 MAYNARD M. METCALP, 



Explanation of the Plates. 



Plate 34. 

 Reference letters. 

 C.f ciliated funnel (dorsal tubercle) n nerve 

 eg coagulum nc nucleus 



d.ep cloacal epithelium ph.h pharyngeal band 



d duct of neural gland ph.ep pharyngeal epithelium 



d.r dorsal raphe p.s.n posterior siphonal nerve 



ep epidermis r.h.S rapheal blood sinus 



g.C ganglionic cord r.d rapheal duct 



gg ganglion (brain) r.n rapheal nerve 



gl neural gland VC vacuole 



Fig. 1. Dorsal view of the ganglion, neural gland and ciliated 

 funnel of Ciona intestinalis L. X 10 diameters. 



Fig. 2. A ventral view of the ciliated funnel (dorsal tubercle) of 

 Ciona intestinalis L. X about 15 diameters. 



Fig. 3. Parasagittal section through the ganglion, neural gland and 

 rapheal organs of Ciona intestinalis. The section is taken a little to 

 the right of the median plane. The figure is a composite drawing made 

 from four consecutive sections. X ^^ diameters. 



Fig. 4. The intersiphonal organs of Ascidia mentula 0. F. M., 

 viewed from the right side. The drawing is a reconstruction from serial 

 cross and longitudinal sections. 



Fig. 5. The ganglion, gland and rapheal organs of Phallusia mam- 

 millata Cuv., viewed from the right side. The drawing is a reconstruc- 

 tion from serial longitudinal sections. 



Fig. 6. A dorsal view of the intersiphonal organs of Rhopalaea 

 neapolitana Phil. X ^ diameters. 



Fig. 7. A sagittal section through the intersiphonal organs of 

 Rhopalaea neapolitana Phil. X '^^ diameters. 



Fig. 8. A sagittal section through the intersiphonal organs of 

 Clavelina rissoana M. Edw. The figure is a composite drawing made 

 from two consecutive sections. X ^^^ diameters. 



Fig. 9. A cross section through the ganglion and neural gland of 

 Clavelina rissoana M. Edw. X ^^'^ diameters. 



Fig. 10. A cross section through the posterior part of the ganglion 

 and through the duct of the neural gland of Clavelina rissoana M. Edw. 

 X 600 diameters. 



