NO. 2346. TWO NEW ACANTHOCEPHALOUS WORMS— VAN CLEAVE 465 



EXPLANATION OF PLATES. 



All figures were drawn from hematoxylin stained permanent mounts with 

 the aid of a camera lucida. 



a, annular lacuna. g, genital opening. 



a r, retractor of anterior region of f, invertor of proboscis, 



body. I, lemniscus. 



b, centra] nervous system. n, subcuticular nucleus. 



c, cement gland. r, proboscis receptacle. 

 (J, dorsal lacuna. s, body spine. 



d r, dorsal retractor of receptacle. t, testis. 



e, egg mass. v r, ventral retractor of receptacle. 



Plate 27, 



randosentis iracundus, new species. 



The scales indicating magnification of figs. 1, 5, 7, and 8 have a value of 

 0.05 mm. ; of fig. 6, 0.1 mm. ; of remaining figures on this plate, 0.01 mm. 

 Fig. 1. — Fully extended proboscis of a mature male from intestine of Aquidens 

 pulcher. 

 2. — Lateral view of a hook from near base of proboscis of a mature female. 

 3. — Lateral view of a hook from near middle of proboscis. 

 4. — Lateral view of a hook from tip of proboscis. 

 5. — Optical section through anterior region of a young female showing 



proboscis receptacle and associated structures. 

 6. — Optical section of a mature male with proboscis inverted. 

 7. — A portion of lacunar system in dorsal anterior region of a male, show- 

 ing irregularity in the dorsal lacuna. 

 8. — A portion of lacunar system from posterior region of same individual 

 as shown in fig. 7, showing irregularities of lacunar system in the 

 region of a subcuticular giant nucleus. 

 9. — An embryo from the body cavity of a gravid female. 



Plate 28. 



Quadrigirrus torquatus, new species. 



The scales indicating magnification of figs. 11 to 15, inclusive, have a value of 

 0.01 mm. ; all others on this plate have a value of 0.1 mm. 



Fig. 10. — Fully extended proboscis and anterior region of body of a young male 

 showing arrangement of proboscis hooks and body spines. 

 11.— Hook from basal circle of proboscis of young female. 

 12. — Hook from third circle of proboscis, same individual. 

 13. — Hook from second circle of proboscis, same individual. 

 14. — Hook from terminal circle of proboscis, same individual. 

 15. — Longitudinal section of an embryo fi'om the body cavity of a gravid 

 female. 

 181404— 21— Proc.N.M.voLr.S 30 



