PLATE 13. 



Fig. 1. Reconstruction of anterior end of Dorymenia aeuta, sliowing nervou.s system. 

 buccal system heavily shaded. 



Fig. 2. Same of posterior end of Strophomenia seandens. 

 Fig. 3. Same of anterior end of Chactoderma erudita. 

 Fig. 4. Same of posterior end of Proneomenia hawaiiensis. 



