352 EHNEST WAKKKN. 



s^). 11., showing the peculiar condition of the hy})ostome, and the plug 

 of digestive endoderm (e.p.). 



Fig. 6. — ^x 150. Median longitudinal section of liydranth of E. 

 angustum. showing the general histology, the inverted perisarc-cuxi at 

 base {p.cp.) and ingested food (/./.) in endodermal plug. 



Fig. 7. — Natural size. Small colony of C lava tell a uiiiltitenta- 

 culata sp.n. on sponge (sp.). 



Fig. 8. — x 35. Side view of C. multitentaculata. showing the 

 liydrorhiza and the liase of hydrocaulus eilfl^edded in sponge. 



Fig. 9. — x 140. Vertical median section of the hydranth of C. 

 multitentaculata, showing the histological structure and the origin 

 of the planoblasts {pi.). 



Fig. 10. — Natural size. Small colony of Tuhularia betheris sp. n. 



Fig. 11. — x 25. Side view of hydranth of T. betheris, showing the 

 semi-erect peduncles or blastostyles bearing clusters of gonophores {go.). 

 Fig. 12. — x 70. Median longitudinal section of hydranth of T. 

 l)etheris, showing basal dilatation (&.f7.)with differentiated endoderm. 

 basal mass of skeletal, "cellular" endoderm (^.M".), and blastostyle {pd.) 

 with gonophores. 



Fig. 13. — Natural size. Small colony of Asyncoryne ryniensis 

 sp. n. growing on the surface of a polychast tube. 



Fig. 14. — x 35. Piece of colony of Asyn. ryniensis with short 

 upright hydrocaulus {H.) carried by liydrorhiza (i?.). The hydranth 

 bears short peduncles with probable planoblasts {pL). 



Fig. 15. — X 70. Median longitiidinal section of hydranth of Asyn. 

 ryniensis, showing hydrocaulus {H.), perisarc groove {p.g.), and 

 secondary endodermal canal {S. E. C.) in liydrorhiza. 



Fig. 16. — x 225. Longitudinal median section of moniliform tentacle 

 with the ectodermal swellings and small nematocysts (s.».). 



Fig. 17. — X 225. Longitudinal median section of capitate tentacle 

 of Asyn. ryniensis with large {l.ti.) and small (.s.??.) nematocysts. 



Fig. 18. — X 45. Stem of Sertularella polyzonias {Lin.) with 

 infected hydranth {c.Tiy.) and with mature galls {g.) of a species of 

 Pycnogonum. 



Fig. 19. — x 45. Stem of S. polyzonias, with a lateral branch {b.) 

 springing from the inside of a hydrotheca, a developing gall {d.g.), and 

 an old empty and broken gall {o.g.). 



Fig. 20. — x 130. Median longitudinal section through gall and 

 hydrotheca of S . polyzonias. It shows a longitudinal dorso-ventral 

 section of enclosed embryo of Pycnogonuin. The gall is lined l)y an 



