200 Southern Cross. 



If we take account of all localities from 40° south latitude south- 

 wards to the Antarctic Continent, we find that the following pelagic 

 Tunicates have been obtained in the area : — 



Pyrosoma gigaideuvi. 



Doliolwn ehrenbergi. 



Salpa costata-tilesii. 



S. echinata. 



S. cordiformis-zonaria. 



S. cylindrica. 



S. runcinata-fusiforiais. 



S. democratica-mucronatd. 



ti. africana-maxima. 



Ap'pendicularia. 



Only two of these species have been found in the corresponding 

 latitudes round the North Pole. 



EXPLANATION OF PLATES. 



Plate XIX. 



i^ig. 1. — Part of the Ijrancliial sac of Boltei/ia pachydennatina ishuwiiig 

 variations. 



Fig. 2. — Another part of the sanie branchial sac. 



Fig. 3. — Styela Jadea, Hrdn., from side, nat. size. 



Fig. 4. — Section of posterior end of same to show thickened pad of mantle 

 and test. 



Fig. 5. — Alimentary canal of styela Jadea. 



Fig. 6. — Some of the eudocarps x 2. 



Fig. 7. — Part of the endostyle. 



Plate XX. 



Fig. 1. — Tylohranchion antardicum, nat. size. 



Figs. 2 and 3. — Ascidiczooids enlarged. 



Fig. 4. — Dorsal tubercle. 



Fig, 5. — Branchial sac. 



Fig. 6. — A papilla. 



Figs. 7, 8, and 9. — Colonies of Distaplia ignota, Hrdn. 



Plate XXI. 

 Figs. 1-10. — Shapes of cohniies of Atopogaster elongata, Hrdn. 



Plate XXII. 



Figs. 1 and 2. — Colonies of Folydinum adareauum. 



Fig. 3. — Systems of ascidiczooids. 



Fig. 4. — Arrangement of pigment. 



Fig. 5. — Common cloacal aperture from inside. 



Fig. 6. — Lower end of a colony. 



Figs. 7, 8, and 9. — -Branchial sacs. 



Plate XXIII. 



Figs. 1 and 2. — Colonies of PnammapUdium nigrum. 



Fig. 3. — Branchial sac of same. 



Fig. 4. — Colony of Fsammaplidium antarcticum. 



Fig. 5. — Section of edge of colony. 



Fig. 6. — Part of branchial sac. 



