522 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



PLATE 53 



Filisoma bucerium, new species 



Fig. 10. Anterior extremity of male showing relations of proboscis to 

 the body, the receptacle of the proboscis and associated 

 structures, and the lemnisci. 



Fig. 1L Detail of tip of same proboscis as shown in Fig. 10. 



Fig. 12. Detailed drawing of proboscis of a male showing distinctive 

 cowhorn-shaped single row of middorsal hooks. 



Fig. 13. Posterior extremity of gravid female showing copulatory 

 cap. 



Fig. 14. Section of body of mature female anterior to copulatory cap, 

 showing uterine apparatus. 



