PLATE li; 



Vi'^s. 1-7, 0-12. Si'clions of Dciryiiicnia ;icul;\. X ')!); Fifj. S. Halomonia gravida. 



Figs. 1, 2 corros])oiul to lines A, R imlicatcd in titj. 7, ])]. 1") (anterior end), and figs. 4, 6 to D, C, 

 in fig. 4, ])1. l) (posterior end). 



Seetlon throiigli dor.so-terminal sense organ. 

 Cross section of ]ienial spine. X 20-"). 

 Longitudinal section of anterior end of liod.\'. 

 Cross section corresponding to line D, fig. 5, pi. 3. 

 Cross section of yonng animal, ])osterior end. 

 Longitudinal section through lia.se of penial s])ine. X 20.5. 

 Section through dorso-terininal sense organ. X 20.t. 

 Section through atrial cavity. 



