PLATE I. 



FIGS. 1, 2, 5, 7, 9. Amphiporua multihastatus. 

 3, 8. Prostoma iniUiiicatuiii. 



4, 6. Baseodiscus antarcticus. 



FIG. 1. Ampltiporus multihastatus, Joubia. Dorsal view of anterior end, showing E., the two groups 

 of eyes. 



FIG. 2. Aiu^iMporus multihastatus. Ventral view of anterior end. M., single opening of the mouth and 

 proboscis-pore ; C.S., cephalic slits. 



Vic. 3. Prostoma umlineatum (Joubin). Dorsal view of the entire animal, x 8. Pr., the partially 

 everted proboscis. 



FIG. 4. Basi'odisciis antarcticus, sp. 11. Ventral view of anterior end, showing G., lateral grooves in 

 which the openings of the cerebral organs are situated; M., mouth ; P.P., proboscis-pore. 



FIG. 5. Amphiporus multihastatus. Transverse section near the anterior end. B.M., basement-mem- 

 brane ; Csec., anterior cajcum of the intestine ; C.M., circular muscle-layer ; D., a genital 

 duct; Ep., external epithelium; G., goiiadial sac (testis) ; L.M., longitudinal muscle-layer ; 

 L.N., lateral nerve-stem; L.P., lateral pouch of intestinal cascum ; Pr., proboscis; P.S., cavity 

 of proboscis-sheath ; Pyl., pyloric canal. 



FIG. G. Baseodiscus antarcticus. Transverse section at about the middle of the body. B.M 1 ., primary 

 basement-membrane ; B.M 2 ., secondary basement-membrane ; C.M., circular muscle-layer ; 

 Ep., external epithelium ; Gl., glandular layer of the integument ; Int., intestine ; L.M 1 ., inner 

 longitudinal muscle-layer ; L.M 2 ., outer longitudinal muscle-layer ; L.N., lateral nerve-stem ; 

 Pr., proboscis ; P.S., cavity of proboscis-sheath. 



FIG. 7. Amphiporus multihastatus. Middle portion of the proboscis, seen by transparency, showing the 

 armature and reserve-stylets. 



FIG. 8. Prtistuina unilineatum. Transverse section in the middle region of the body. Ep., external 

 epithelium ; Int., intestine ; L.N., lateral nerve-stem ; Ov., ova ; Pi., dorsal band of pigment ; 

 P.S., cavity of proboscis-sheath. 



FIG. 9. A-Hipltiporm mitltihastattis, 9 Transverse section in the middle region. B.M., basement- 

 membrane ; C.M., circular muscle-layer; G., goiiadial sacs, containing ova; Int., intestine; 

 L.M., longitudinal muscle-layer; L.N., lateral nerve-stems; P.S., cavity of proboscis-sheath. 



