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 proboscis 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. L, 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. 1., cam. luc. 



Fig. 18. — Transverse section through the posterior region of collar. Zeiss 

 A (without lowest lens), oc. 1., cam. luc. 



Plate VII. 

 -Transverse section of ventral part of collar slightly posterior to 



fig. 18, showing the ventral septum. Zeiss A., oc. 1., cam. luc. 

 -Transverse section (slightly oblique) through the branchial region 



of a sexually immature individual. Zeiss A (without lowest 



lens), oc. 1., cam. luc. 

 -Section of a single gill from a vertical longitudinal series. Zeiss 



C, oc. 1., cam. luc, 

 -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 matui'e 



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. 



