86 



Introduction to Animal Morphology. 



endoderm, with a pouch of the somatic cavity con- 

 tained (Fig. 12, A), and are said to be adelocodonic 

 (a, S»)Xoc, KwSwv). The wall or perigonium of the sac 

 consists of three layers derived from the ectoderm 



Fig. 12. 



A. Sporosac. K. Sporosac with incipient radial canals. C. Phanerocodonic 

 gonophore ; s., spadix. D. Gonocheme, section ; r.c, radial canal ; m. mouth ; w., 

 velum ; /., tentacle ; s., sexual products. E. Carmarina hastata ; m., mouth, with 

 tongue-like process ; d., disk ; c, circular canal ; s., sporosacs ; c.r., cartilaginous 

 ring; v., velum. 



(iecto-, meso-, and endo-theca), having in the centre a 

 tubular, cylindroidal stalk of the endoderm (spadix. 

 Fig. 1 2, C, .y.), on whose wall, under the endotheca, 

 the sexual products form. From the somatic cavity 

 in the base of the spadix, four radial canals lined by 

 endoderm may traverse the mesotheca (homologous 

 with that part of the tentacles of a hydranth included 

 in the base of the hypostome, seen in section in Fig. 



