546 GILBERT C. BOURNE. 



PLATE 42, 



Fig. 27. — Portion of a transverse section throui^h Mussa distans. 

 Mes. Mesenteries. Sep. space occupied by a septum. Disscp. Space occu- 

 pied by a dissepiment, ca. Caiicoblasts. dc. Desmocytes. en. Endoderm. 

 m. I. Limiting membrane. Zeiss B, oc. 4. 



Pig. 28. — Four desmocytes of Mussa dislaus, magnified 1000. u. 

 Nuclei witii surrounding cytoplasm of the parent cells of the desmocytes. 

 mff. Mesoglcea. 



Fig. 29. — Caiicoblasts of Mussa distans, magnified 1000. vac. Vacuoles 

 containing microsomata. tuff. Mesoglcea. e/i. Endoderm. 



Fig. 30. — Surface view of a portion of the calicoblast layer from the lateral 

 surface of a septum of Caryophyllia Smithii, showing a rudimentary 

 desmocyte, dm. The vacuolated and pitted character of the protoplasm is 

 indicated. Zeiss, J^ I'oi^- imm., c. oc. 4. 



Fig. 31. — Optical section of a septal granulation of Caryophyllia, showing 

 that it is made up of a number of bunches of radiating fibro-crystals. Zeiss, 

 ■^ hom. imm., c. oc. 4. 



Fig. 32. — Surface view near the growing edge of a palus of Caryophyllia, 

 showing the liemisphajroidal bunches of fibro-crystals of which it is com- 

 posed. 



PLATE 43. 



Fig. 33. — Part of a transverse section through the edge-zoue of Euphyllia. 

 ec. Ectoderm with two kinds of gland-cells and nematocysts. dc. Desmocytes. 

 en. Endoderm. mes. Extra-thecal portion of a mesentery, m//. Mesoglcea. 

 ca. Caiicoblasts. 



Fig. 34. — Part of a section of the same species, showing the fold of the 

 soft tissues over the inner and upper edge of a septum. e>i. Endoderm. 

 m^. Mesoglcea. ca. Calicoblast layer consisting of nuclei lying in a layer of 

 vacuolated protoplasm. 



Fig. 35. — Surface view of a group of desmocytes of Caryophyllia 

 Smithii. Cur. Fragments of corallum adherent to the desmocytes. p. c. 

 Parent cells of desmocytes. 



Figs. 36 — 39. — Stages in the development of desmocytes of Caryophyllia. 

 Lettering as in the previous figures, gl. c. in Fig. 39 is a gland-cell filled 

 with highly refringent globules. Such gland-cells are often very abundant in 

 the endoderm immediately overlying active caiicoblasts. 



Fig. 40. — Part of a transverse section of Caryophyllia taken at the point 

 where the tissues turn over the edge of the theca between two septa to form 

 the edge-zone. en. Endoderm of the intra-thecal portion of the polyp. 

 eii' . Endoderm of the edge-zone. mg. Mesoglcea. ca. Caiicoblasts. 



