AND DEVELOPMENT OF MYKIOTHELA. 
573 
Fig. 3. Longitudinal section through summit of tentacle, much magnified. 
a. Rod-like tissue ; b. Pedunculated capsules. 
Fig. 4. Thread-cells. 
a. Oviform thread-cell in its quiescent state ; a'. Same, with the filament 
ejected ; b. Fusiform thread-cell in its quiescent state ; V . Same, with the 
filament ejected. 
Fig. 5. Cells of ectoderm of tentacle liberated at the commencement of putrescent 
histolysis. In each of the two larger cells may be seen a thread-cell. 
Fig. 6. A portion of the hyaline lamella with its attached clavate tissue, from the body 
of the hydranth. 
a. Clavate tissue ; b. Fibrillated layer of the hyaline lamella ; c. Delicate 
structureless layer of the same lamella. 
Fig. 7. Some of the rods of the bacillar tissue of tentacle, greatly magnified. 
Fig. 8. One of the pedunculated sacs, with its contents, from the tentacle isolated. 
Fig. 9. The capsule, with its contained cord liberated from the pedunculated sac. 
Fig. 10. The capsule after the ejection of the cord, which is still attached by one end 
to its summit. 
Fig. 11. Distal extremity of a clasper. 
a. Endoderm ; b. Hyaline lamella ; c. Clavate tissue ; d. External layer 
of ectoderm ; e. Extension of ectoderm with its clavate tissue greatly deve- 
loped over the distal end of the clasper. 
Fig. 12. Isolated cells of the clavate tissue from the distal extremity of a clasper. 
Fig. 13. Distal extremity of one of the transitory arms of the actinula. 
a. Modified claviform tissue, which here forms the whole thickness of the 
ectoderm ; b. Endoderm with axial cavity ; c. Capitulum. 
Fig. 14. Pedunculated sac from the capitulum of one of the transitory arms of the 
actinula. 
a. The pedunculated sac with its contents still undisturbed ; b. The capsule 
liberated from the sac and with its spiral cord ejected. 
Fig. 15. Distal extremity of actinula, showing the peculiar development of the clavate 
tissue at the extreme end (a), which acts as a sucker of adhesion. 
PLATE 57. 
Fig. 1. Very early stage in the development of the gonophore. 
a. Offset from the endoderm of the blastostyle which has pushed itself into 
the ectoderm ; b. Gonogenetic chamber filled with a granular plasma ; c. 
Diverticulum from the cavity of the blastostyle ; d. Ectoderm of the blasto- 
style as yet scarcely raised above the general surface. 
Fig. 2. More advanced stage (female) ; the gonophore has formed a very decided pro- 
jection from the external surface of the blastostyle, and the gonogenetic 
chamber has begun to show a differentiation in its contents. 
MDCCCLTXV. 4 G 
