STOLOX FOK.MATIOX IX SPECIES OF TRYPAXOSYLLIS . 445 
cytes with abundant cytoplasm, mes. Mesoblast. mes'. Unsegmented 
mesoblast of stolon, mes. n. Nuclei of mesoblast. mes. r. Fibrous 
residue of mesoblast of stolon. pecZ. Pedicle of stolon, n. c. Nerve- 
cord. n. s. Notopodial setae, n. m. Notopodial muscles, pr. Z. Lip of 
proliferating cushion where formation of new stolons takes place. 
sep. Embryonic septum in stolon, .sj}. c. Spermatocytes, st'. First- 
formed stolon. Z, c. Tentacular cirrus, v. c. Ventral cirrus. 
PLATE 23. 
Fig. 1. — Ventral surface of Trypanosyllis gemmipara '(II), 
showing regenerating tail. X 50. 
Fig. 2. — Ventral surface of posterior end of reproducing individual 
(VIII). showing youngest rows of stolons. X 24. 
Fig. 3. — Dorsal surface of same, showing older stolons and genital 
appendage of stock, x 20. 
Fig. 4. — Ventral sui-face of posterior end of another rei^roducing 
individual (IX). X 12. 
Fig. 5. — Dorsal surface of same. X 12. 
Fig. 6. — Dorsal view of stolon (detached genital appendage) from IX. 
Fig. 7. — Dorsal view of head of Trypanosyllis crosslandi. 
Fig. 8. — Y^entral surface of posterior end of reproducing male (ii). 
Fig. 9. — Dorsal surface of same, showing mature stolons attached to 
attenuated terminal segment. 
Fig. 10. — Ventral surface of posterior end of reproducing female (iii). 
Most of the stolons had detached themselves and pi'oliferation ceased. 
PLATE 23 BIS. 
Fig. 11. — Longitudinal section showing a small part of the proli- 
ferating cushion in Trypanosyllis crosslandi (1) bounded by ali- 
mentary canal, showing nuclei of connective tissue and invading leuco- 
cytes. X 1320. 
Fig. 12.— Longitudinal section from the same series as fig. 11, showing 
boundary of free space of ccelom and mesoblast of proliferating cushion. 
Leucocytes of two kinds free and invading mesoblast. x 1320. 
Fig. 13. — Section through proliferating lip and youngest stolon in 
T. gemmipara (VIII). x 550. 
Fig. 14. — Longitudinal section through young stolon in same series 
as Fig. 13, showing segmentation of mesoblast and the first entrance of 
nerve-fibres, x 25i >. 
