Plate III. 

 Pourtalesia JefFreysi Wyv. Thoms. 



The anibiilacral system coloured. 



Pig. 10. The ventral half of the skeleton, seea from the inside. The heteronomy marked as in tig. 9. 



Fig. 11. The dorsal half of the skeleton, seen from the inside. 



Fig. 12. The infra-frontal recess seen from the peritoneal cavity, and from the left. 



Fig. 13. Longitndinal section of the hindmost part of the skeleton, the candal prolongation, the periproct, 



and the anal raembrane: am. 

 Fig. 14. The dorsal termination of the ambulacnim V, from the inside. 



