STAGE "F". 5. DAYS. 



Although "?" is separated from the stage last 

 described by a, considerable space of tine, the chan- 

 ges in the larva which have boon brought about are 

 aasy to follow. 



The larva is eonsiderbly larger than in "E" 

 and has reached itd full development. From this time 

 on the larval" or-^an gradually degenerates and io 

 finally completely absorbed by the developing star. 

 Compare #i:i3.22 and 31. Io. 



Th2 external form of the larva has been chang- 

 ed by the appearenee of a number of elevations and 

 depressions in its outer surface: the ciliated bands 

 being elevated upon circular ridges ,Fig"i22,cb 1,2, 

 3 and4., while at points on -the sides of the disk 

 beyond the end tentacles, projections in the ectoderm 



nade their appearenee, these being the rudiments 

 of the ophiuran arms .Fig. 22.1 ,11 ,111 ,IVand V. 



The larval organ is cylindrical but the disk 

 has continued its dor so-ventral flattening. Compare 

 Figs, 22. and 2G . 



The first ana second ciliated bands are sit- 

 uated in the same places as in "E" . T^ie third while 



