ON JULINIA. 15 



PLATE 1. 



Fig. 1. — General view of colony slightly reduced. 



Fig. 2. — A single system of ten individuals x 7. In the centre of the 

 system is the irregularly-lobed cloacal orifice ; on the outer side of each 

 ascidiozooid the endostyle is seen shining through. 



Fig. 3. — A single ascidiozooid seen from the left side x 20. This figure 

 illustrates the form of the branchial sac, the convoluted endostyle, and the 

 relations of the incubatory pouch and atrial languet. In the abdomen the 

 ovary and part of the vas deferens are seen on the dorsal side of the intestinal 

 loop. 



Fig. 4. — Ventral vievp of abdominal region, showing the oblique folds in the 

 stomach wall, and the position of the heart and part of the vas deferens in the 

 loop of the gut. The origin of the vascular process is seen on the lower side 

 of the intestine. 



Fig. 5. — Bud lying beside vascular process. 



Fig. 6. — Younger bud near club-shaped end of vascular process. 



Fig. 7. — View of part of common cloacal chamber seen from within, showing 

 four atrial languets pointing inwards and meeting together. In one indi- 

 vidual of the system the oral region is also shown. The roof formed to the 

 common cloacal chamber by these converging atrial languets is not to be seen 

 from the outside, it being covered in its turn by a second roof of test- 

 substance. 



Fig. 8. — Oral region of an ascidiozooid seen from within, showing the six- 

 lobed buccal orifice, the hexagonal ring of twelve tentacles, the peripharyngeal 

 band connected dorsally with the dorsal tubercle and ventrally with the endo- 

 style ; the nerve ganglion, the first row of stigmata, and the trabeculse con- 

 necting the stigmatic wall with the atrial wall are also seen. 



Fig. 9. — Transverse section through one half of the colony x 4, showing 

 the position of the ascidiozooids, the distribution of the vascular processes 

 through the matrix of the colony, and the zone of problematic vesicles referred 

 to on p. 3 as possibly representing degenerated zooids. 



Fig. 10. — Cell elements from the test supposed (p. 4) to be phagocytes. 

 Zeiss, -^th hom. imm., 2. 



Fig. 11. — Spicules from test. Zeiss, D. D., 2. 



