PLATE XVI. 
Figs. 1-7. Colella elongata, n. sp. 
Figs. 8-16. Colella concreta, n. sp. 
Fig. 17. (?) 'pyriformis, n. sp. 
dbd. Abdomen of Ascidiozooid. 
at. Atrial aperture. 
hr. Branchial aperture. 
d.l. Dorsal lamina. 
d.t. Dorsal tubercle. 
en. Endostyle. 
fd. Fold in wall of stomach. 
gr. Groove between folds. 
h.m. Horizontal membrane 
sac. 
i. Intestine. 
1. Dorsal languet. 
ov. Ova. 
p.p. Peripharyngeal band. 
r. Rectum. 
sph. Sphincter. 
st. Stomach. 
t. Test. 
th. Thorax of Ascidiozooid. 
tn, tn'. Tentacles. 
t.v. Spermatic vesicles. 
v.ap. Vascular appendage. , 
v.d. Vas deferens. 
Fig. 1. Colony of Colella elongata; natural size. 
Fig. 2. Transverse section of colony of Colella elongata ; natural size. 
Fig. 3. Part of a transverse section of Colella elongata; magnified (S., 1 incli). 
Fig, 4. Part of the test from the centre of the head of Colella elongata, showing the 
vascular appendages ; magnified (S., 1 inch). 
Fig. 5. An Ascidiozooid of Colella elongata, seen from the right hand side ; magnified 
(S., 1 inch). 
Fig. 6. Part of a young Ascidiozooid of Colella elongata, showing the alimentary 
canal ; highly magnified (S., ^ inch). 
Fig, 7. Part of the circle of tentacles oi Colella elongata; highly magnified (S., ^ inch). 
Fig. 8. Large colony of Colella concreta; natural size. 
Fig. 9. Ascidiozooid of Colella concreta, seen from left hand side ; enlarged. 
Fig. 10. Part of the vascular appendage of ; highly magnified (S., ^ inch). 
Fig. 11. Ascidiozooid of Colella concreta, from left hand side; magnified (S., 1 inch). 
Fig. 12. Part of mantle of Colella concreta ; magnified (S,, 1 inch, enlarged). 
Fig. 13. Part of branchial sac of Colella concreta; magnified (S., 1 inch, enlarged). 
Fig. 14. Dorsal part of anterior end of Ascidiozooid of Colella concreta, showing 
tentacles, dorsal tubercle, languets, &c,; highly magnified (S., ^ inch). 
Fig. 15, Part of waU of stomach of Colella concreta, spread out and seen from inside to 
show the closely placed longitudinal folds ; highly magnified (S., ^ inch). 
Fig. 16. The male reproductive organs of Colella concreta; magnified (S., 1 inch). 
Fig. 17. Colony of (^) pyriformis; natural size. 
