Plate IV. 



Fi'f. 1. — Oîkoplcitra riifescen>i Fol. Left side view of the trunk. 



Y\a, 2. — Ditto. Kight side view of tlie trunk, to show the iuternal 



structure. 

 Fio". 3. — Ditto. Ventral view of the trunk. 

 Fig. 4. — Ditto. Left side view of the alimentary canal. 

 Fig. .3. — Ditto. Ventral view of the alimentary canal and genital glands. 

 Fig. G. — Ditto. Back side view of the entire body. 

 Fitr. 7. — Ditto. Riiiht side view of the trunk of a female, to show the 



internal structure. 

 Fig. 8. — Oikopleura dioica Fol. Left side view of the trunk of a male 



individual. 

 Fig. 9. — Ditto. Left side view of tlie trunk, to show the rows of the 



interposed layer of the " Hans- Anlage.*' 

 Fig. 10. — Ditto. Ventral view of the alimentary canal. 

 Fiii. 11. — Ditto. Back side view of the entire body. 

 Fig. 12. — Stegosoma magnum Langerhans. Ventral view of genital glands 



in an advanced state of development. 

 Fig. 13. — Ditto. Biglit side view of the trunk, to show the internal 



structure. 

 Fig. 14. — Ditto. Hind view of the alimentary canal and of immature, 



band-like, genital glands. 

 Fig. 15. — Ditto. Terminal part of the tail, lo show the group of flat 



gland-like cells. 

 Fig. Hi. — Ditlo. Left side view of the trunk. 

 Fig. 17. — Ditto. Entire bodv from behind. 



