PLATE XIX. 



CORYMORPHA NUTANS. 

 FlO. 



1. The entire hydrosoma, magnified; a, papilliform processes from the stem; h, h, filamentary 



appendages emitted from the proximal end. 



2. A group, natural size, as it appears when confined in an aquarium, the proximal ends 



plunged into the sandy bottom. This may fairly be taken as representing the mode of 

 existence of Corymorplia nutans in its natural habitat at the bottom of the sea. Some 

 planoblasts just liberated are seen swimming about. 



3. One of the branched peduncles from the gonosome carrying gonophores in various stages of 



development, more magnified than fig. 1. 



4. A planoblast shortly after liberation ; its tentacle contracted. Much magnified. 



5. Mature male planoblast, magnified. 

 5a. The same, natural size. 



6. Transverse section of the stem about the middle of its length ; a, delicate external pellicle ; 



h, ectoderm ; c, fibriliated layer, d, peripheral portion of endoderm composed of small 

 spiierical cells with coloured granular contents, and excavated by longitudinal canals ; 

 e, axial portion of endoderm composed of large polygonal cells with clear homogeneous 

 contents. 



7. Longitudinal section of hydranth ; a, distal portion of hydranth cavity; b, proximal portion 



communicating with « by a narrow axial channel, and receiving the longitudinal canals, 

 c, of the stem ; d, ectoderm ; e, outer clear-celled portion of endoderm ; /, inner portion 

 of endoderm lining the hydranth cavity, and composed of cells with coloured granular 

 contents ; g, base of proximal set of tentacles ; h, base of distal set ; /, peduncles of the 

 gonophores. 



8. Portion of a proximal tentacle of the hydranth seen in longitudinal section. 



9. Portion of a distal tentacle of the hydranth seen in longitudinal section. 



10. One of the papilliform processes of the stem extended. 



11. Same, contracted. 



12. Free frustule of Corymorpha nutans contained within its delicate chitinous tube which 



adheres to the sides of the jar. 



13. The same body after it has become fixed by one end and developed a hydranth from the other. 



14. The same, more advanced. 



