10 EMBRYOLOGICAL MO:^TOGRAPHS. 



11. Embryo after tlip formation of the mouth. A small cluster of cells, not represented in the figure, is 



represented in Kleinenberg's figure just above the mouth. Tlie tentacles appear in pails, as lioUow 

 processes. 



12-22. Development of Candelabrum phryr/ium, De Blain. Myriotluhi. phrygia, Fab.). From Allman, On the 

 Structure and Development of Myriothela. Phil. Trans. lioy. Soc. CLXV., PI. LVII., fig.s. 1, 2, 3, 4 ; 

 PI. LVIII., figs. 1, 2, 4, 5, 6, 7, 8. 



12. Very young buil, which later forms a gonophore. ch. Epiblast forming a slight elevation. 7i /<'. Accompany- 



ing hypoblastic prolongation into the epiblastic prominence, fi. Cavity filled with granular protoplasm. 

 ff. Divertieuliim from the chamber or cavity of the blastostyle. 



13. "More advanced stage (female); the gonophore has formed a very decided projection from the external 



surface of the blastostyle, and the gonogenetic chamber (m) has begun to show a differentiation in its 

 contents." Allman. cb'. Epiblastic prouiinenee above the surface of the bla.stostyle. hb. Hypoblastic 

 layer, /i. Gonogenetic chamber. <r. Diverticulum from the cavity of the blastostyle. 



14. The female gonophore still more developed, mb. Membrane, ix. Gonogenetic chamber. <t. Diverticulum 



from the cavity of tlie blastostyle. 



15. A gonophore older than the last. 



The wall of the gonophore in a stage of the same, ohler than figure 15, is ruptured, and the contents 

 escape. It (the portion escaping) is, however, grasped by a peculiar clasper, which holds fast to its capsule 

 by a sucl<er-like body, and certain changes take place while it is in this embrace. 



16. Planula. A segmentation about which there is little known has taken place, and the planula has an outer 



layer ( cb), an inner layer {hb), while a cavity (cor.) has been formed by the liquefaction of the central 

 part ol the mass. It is enveloped in a membrane (mb), and enelos(;d in a capsule, which is firmly held by 

 the claspers. There are no cilia. 



17. Embryo with minute pits (X) forming the orifices of invagin.ations of the wall of the planula, and enclosed in 



a capsule {cp). These invaginations are composed of two layers, and later, when reversed, form the pro- 

 visional appendages {/.a'). 



18. Embryo still enclosed in a capsule and held by the claspers, both of which structures are not represented. 



The invaginatcd appendages {ta'} have been turned outward. 



19. Embryo taken from a capsule in which small papilhe have begun to form at one end. These (tn) later elon- 



gate into the permanent tentacles, ta'. Piovisional appendages. 



20. Embryo free from the capsule, which has begun to fasten itself at one extremity by a disk (j'). 17. Position 



of the mouth, ta. Permanent tentacles, ta'. Transitory arms. 



21. The larva iiermanently fastened, possessing permanent arms [trt), but destitute of transitory appendages. 



22. Free, locomotive embryo (actinula), just after its escape from the capsule, and younger than the earliest 



attached condition (20). ta. Permanent arms. la'. Transitory arms. f. Disk for fixation, -n. iloutli 

 region. The arms are rei)resented extended. When retracted, they have the form of ovoid bodies of small 

 size. The larva remains in the actinula condition only a few days. 



