BRYOZOA OF THE PHILIPPINE REGION 85 



Fig. 15.— Family Flustridae Smitt, 1867 



(Explanatory remarks) 



A. Embryo of Flustra foliacea Linnaeus, 1758 X56 (after Barrois, 1877); c, 

 coronna; est, stomach; /, aboral face; ph, pharynx; o, mouth of gastrula; S, aboral 

 face; si, separating thread in terminal bud and inferior portion of the aboral face; 

 vt, terminal bud of the body. 



B. Flustra securifrons Pallas, 1766. Meridian section of an embryo showing 

 the oral ectoderm invaginated and forming the outline of the interior sac; c, 

 mantle; bl, blastocoele; cal, calotte; co, coronna; eclo, ectoderm; one, central nerve 

 organ of the embryo; si, internal sac. (After Calvet, 1900.) 



C-E. Flustra membranaceo-lruncata Smitt, 1867. C. Drawing showing 

 arrangement of the principal organs in the zooecium. D. Sketch illustrating 

 arrangement of the muscles (after Vigelius 1884). Distal avicularium present. 

 E. Sketch showing movement of the mandible of the avicularium (C-E, after 

 Vigelius 1884); an, anus; ca, cardiac region of the stomach; coec, stomachic 

 coecum; dw, distal wall; est, stomach; h, lateral wall of the zooecium; I, pivot of 

 the avicularian mandible; oes, esophagus; ov, ovarium; ph, pharynx; pm, parietal 

 muscles; ps, mesenchymatous tractus; pv, proximal wall; py, pyloris; r, rectum; 

 re, large retractor muscle of the polypide; rk, circular canal; t, tentacles; ts, 

 tentacular sheath; u, mandible of the aviculariumj um, mandibular muscles; 

 i, aborted polypide = ciliated organ of the avicularium. 



F. Flustra pisciformis Busk, 1852. Anatomic structure of an entire zooecium; 

 the distal group of parietal muscles (pm') probably act as divaricators of the oper- 

 culum (after Harmer, 1902); cae, coecum of the stomach; dw, distal wall; fl, 

 vertical flange of operculum; occl, occlusor muscles of operculum; pd, parietal 

 diaphragm muscles; pm, parietal muscles; pm', distal group of parietal muscles; 

 pvm, parieto-vaginal muscles and bands; rm, retractor muscles of polypide; 

 vest, vestibule ( = diaphragm). F.'. Distal view of operculum, showing the 

 vertical flange, fl. G. Operculum, X23. 



H-I. Flustra securifrons Pallas, 1766. H. Mesenchymatous network and 

 leucocytes observed on the living animal in the general cavity of an adult zoo- 

 ecium; aa', univesicular leucocytes; b, pleurivesicular leucocytes (after Calvet, 

 1900). I. Section of a rudimentary mass of a regenerated polypide making part 

 of the mesenchymatous network. This figure shows very well the essentially 

 mesenchymatous origin (tm) of the regenerated polypide. The polypidian mass 

 (rp) is removed from the zooecial walls and some distance from the brown body 

 (eft). (H, I. After Calvet, 1900.) 



J. Flustra foliacea Linnaeus, 1761, Two egg shaped ovicells, X40, (G-J, 

 after Levinsen, 1909). 



K. Flustra securifrons Pallas, 1766. K. An ovicell from the frontal surface, 

 X40. The ovicellarian operculum, the proximal end of its muscles and the two 

 cryptocyst processes (dw) are seen between the ovicell and the zooecial operculum. 

 2182—29 7 



