PLATE XXXIII. 
Figs. 1-8. Didemnum aurantiacum, n. sp. 
Figs. 9-15. Leptoclinum ruhicundum, n. sp. 
hr. Branchial aperture. 
en. Endostyle. 
n.g. Nerve ganglion. 
p.j). Peripharyngeal band. 
sg. Stigmata of branchial sac. 
sp. Calcareous spicule in test. 
spA. Sphincter. 
t.c. Test cells. 
tn. Tentacles. 
tr. Transverse vessel of branchial sac. 
v.ap. Vascular appendage. 
Fig. 1. Qolonj oi Didemnum aurantiacum ; natural size. 
Fig. 2. A small portion of the surface layer of test of Didemnum aurantiacum; 
enlarged. 
Fig. 3. One of the branchial apertures seen from the surface; magnified (S., 1 inch). 
Fig. 4. Section of the test in its deeper part ; highly magnified (S., J inch). 
Fig. 5. One of the branchial apertures seen from the inside, showing sphincter muscle, 
and three lobes ; highly magnified (S., \ inch). 
Fig. 6. Spicules from the test ; a shows the most common form ; highly magnified 
(enlarged from S., j inch). 
Fig. 7. A small portion of the wall of the large testis, with the vas deferens coiled 
round it ; magnified (S., 1 inch). 
Fig. 8. One of the large tailed larvae of Didemnum aurantiacum ; magnified (S., 1 inch). 
Fig. 9. Colony of Leptoclinum ruhicundum; natural size. 
Fig. 10. Part of the outer layer of the colony, including the anterior parts of the 
Ascidiozooids, seen from the inside; magnified (S., 1 inch). 
Fig. 11. Part of the surface of the colony, seen from the outside; magnified (S., 1 inch, 
enlarged). 
Fig. 12. horn t)iQ oi Leptoclinum ruhicundum ; highly magnified (S., inch). 
Fig. 13. Part of the branchial sac of a young Ascidiozooid of Leptoclinum ruhicundum; 
highly magnified (S., ^ inch). 
Fig. 14. Part of the branchial sac of an adult Ascidiozooid of Leptoclinum ruhicundum; 
highly magnified (S., ^ inch). 
Fig. 15. The anterior end of an Ascidiozooid, seen from the inside, and showing 
endostyle, nerve ganglion, peripharyngeal band, tentacles, sphincter, 
branchialaperture, &c.: highly magnified (S., ^ inch). 
