42 
ON A NEW SPECIES OF ENTEROPNEUSTA. 
Plate iv. 
Fig. 11. — Transverse section of proboscis neck of an individual with two 
proboscis pores. Zeiss A., oc. 2., cam. luc. 
Fig. 12. — Similar section of an individual with a single median proboscis 
pore. Zeiss A., oc. 2., cam. luc. 
Fig. 13. — Dorsal view of pi'oboscis skeleton. ( x about 30). 
Fig. 14. — Vertical longitudinal section (nearly median) through the point 
of union of the proboscis neck with the collar. Zeiss A 
(without lowest lens), oc. 1., cam. luc. 
Plate v. 
Fig. 15. — Vertical longitudinal section through the dorsal region of collar 
Zeiss A., oc. 1., cam. luc. 
Fig. 16. — Dorsal median portion of a transverse section through the anterior- 
region of collar. Zeiss A., oc. 1., cam. luc. 
Plate vi. 
Fig. 17. — Transverse section through the collar passing through the opening 
of the notochord into the throat and through the circular 
vessel fold. Zeiss A (without lowest lens), oc. ] ., cam. luc. 
Fig. 18. — Transverse section through the posterior region of collar. Zeiss 
A (without lowest lens), oc. 1., cam. luc. 
Plate vii. 
Fig. 19. — Transverse section of ventral part of collar slightly posterior to 
fig. 18, showing the ventral septum. Zeiss A., oc. 1., cam. luc. 
Fig. 20. — Transverse section (slightly oblique) through the branchial region 
of a sexually immature individual. Zeiss A (without lowest 
lens), oc. 1., cam. luc. 
Fig. 21. — Section of a single gill from a vertical longitudinal series. Zeiss 
C. , oc. 1., cam. luc. 
Fig. 22. — Transverse section of a sexually immature individual, just behind 
the branchial region. Zeiss A (without lowest lens), oc. 1., 
cam. luc. 
Plate viii. 
Fig. 23. —Transverse section through the genital region of a sexually mature 
male, passing through a genital pore. Zeiss A (without 
lowest lens), oc. 1., cam. luc. 
Fig. 24. — Transverse section through the hepatic region. Zeiss A., oc. L, 
cam. luc. 
Fig. 25. — Transverse section through the abdominal region showing the two 
ciliated bands. Zeiss A., oc. 1., cam. luc. 
Fig. 26. — Ripe spermatozoa. Zeiss D., oc. 4., cam. luc. 
