PLATE XII. 



The lettering is the same in all the figures. 



a Acorrtia. 



b Mesenteric filaments 



c Stomata in the septa. 

 c ' Perioral stomata. 

 c- Marginal stomata. 

 at Cuticle. 



d Glandular streaks of the mesen- 

 teric filaments. 



e Ciliated streaks of the mesenteric 

 filaments. 

 ek Ectoderm. 

 en Endoderm. 



g Reproductive organs. 



h Septa, rh Directive septa. 



i Oral disk. 



k Wall. 

 I Pedal disk. 

 m Muscles. 

 mm Mesodermal muscles. 

 ml Longitudinal muscles of the septa. 

 ml 1 Retractor. 

 mp Parietobasilar muscle. 

 ■mt Transverse muscles. 

 mr Radial muscles of the oral disk 

 and longitudinal muscles of the 

 tentacles 

 ms Ci rcular muscle of the wall. 

 me Mesoderm. 

 n Urticating cells. 

 o Ovicells. 



All statements given as to magnifying powers have reference to Zeiss's system. 



Oc. 1. Oc. 2. 



a 1 6 10 D 



A 55 70 F 



C 95 125 J 



A with unscrewed front lens (unscr. A) magnifies with Oc. 1 : 30 times ; 



p Filamental apparatus of the ovicells. 

 ;> l Process of the ovicell. 

 p^ Apical set of epithelial cells. 



)■ Marginal spherules. 

 rh Directive septa. 



s (Esophagus. 

 so Openings of the cesophagus into 



the radial chambers. 

 sr (Esophageal grooves. 

 sz Lappets of the cesophagus. 



t Tentacles and the openings homolo- 

 gous with them. 

 I 1 Principal tentacles. 

 t - xVccessory tentacles. 



v Openings of the pedal disk. 



The magnifying powers amount to 



Corallimorplius rigidus. D, Oc. 2 (figs. 1-7). 



Figs. 1-4. Young ovicells in the endoderm ; in figs. 2 and 3 two cells depicted in the 

 act of migrating into the mesoderm. 



Fig. 5. Ovicells with filamental apparatus ; the epithelial cells of the filamental 

 apparatus still lie completely in the epithelium. 



Fig. 6. Ovicells with filamental apparatus ; the epithelial cells of the filamental 

 apparatus migrating into the mesoderm. 



Fig. 7. Ovicells with filamental apparatus. 



Halcampa clavus. D, Oc. 1 (figs. 8, 9, 11). 



Figs. 8 and 9. Two ovicells of different ages with the epithelial apparatus. 

 Fig. 11. Ovicells which lie partly in the endoderm, partly in the mesoderm. 



Cereus spinosus (fig. 10). 

 Fig. 10. Transverse section through an acontium of Cereus spinosus. C, Oc. 2. 



