LIST OF ILLUSTRATIONS XIII 



Page 



13. Opercula of Buffonellaria. A, B. divergens Smitt, 1873. B. B. reticu- 



lata, new species 88 



14. Stylopoma spongites Pallas, 1766. A. Mandible of an interzooecial 



avicularium. B. Operculum 92 



15. Genus Schizopodrella Canu and Bassler, 1917. A-C. Schizopodrella 



pungens, new species. A, B. Two opercula, X 85. C. Mandible, 

 X 85. D, E. Schizopodrella floridana Osburn, 1914. D. Oper- 

 culum. E. Mandible of a large avicularium. F, G. Schizopo- 

 drella falcifera, new species. F. Operculum. G. Mandible of 

 large interzooecial avicularium , 94 



16. Gemellipora glabra Smitt, 1873. A, B. Two aspects of the operculum, 



X 85 99 



17. Opercula of Gemelliporidra Canu and Bassler, 1927. A-C. Gemelli- 



poridra typica Canu and Bassler, 1927. Ordinary, elongate and 

 transverse opercula, X 85. D, E. Gemelliporidra magniporosa, 

 new species. Two opercula showing variation, X 85. F, G. 

 Gemelliporidra aculeata, new species. F. Rare form of operculum. 

 G. Ordinary operculum with the thick part of inner line indicating 

 the insertion of the opercular muscles 101 



18. Hippoporina cleidostoma Smitt, 1873. A-E. Different forms of the 



operculum which is much chitinized 104 



19. Opercula, X 85. A. Hippadenella floridana, new species. B. Hippo- 



diplosia pertusa Esper, 1894. The thickened portion of the inner 

 line indicates the place of the opercular muscles. C. Hippomenella 

 rubra, new species 106 



20. Opercula of Microporella. A. Microporella ciliata Linnaeus, 1758. 



B, C. Microporella ampla, new species. D. Lepralia palliolata, 



new species. Operculum, X 85 109 



21. Smittina spathulata Smitt, 1873. A, B. Mandibles of large avicularia, 



X 85. C. Operculum, X 85. D. Mandible of small avicularium, 



X 85 • 114 



22. Family Smittinidae. A. Smittina labellum, new species. Operculum, 



X 85 doubtfully referred here. B. Umbonula undulata, new species. 

 Operculum, X 85. C, D. Palmicellaria aviculifera, new species. 



C. Operculum, X 85. D. Mandible, X 250. E, F. Rhampho- 

 stomella magnirostris , new species, E. Mandible, X 85. F. Large 

 mandible, X 85. G, H. Smittina labellum, new species. Two 

 opercula, X 85 117 



23. Appendages of Reteporidae. A. Retepora marsupiata Smitt, 1873. 



Operculum, X 85. B, C. Schizellozoon elongatum, new species. 



B. Mandible of a frontal avicularium, X 85. C. Operculum, X 85_ 122 



24. Cigdisula serrulata Smitt, 1877. A, B. Opercula, X 85 126 



25. Bracebridgia subsulcata Smitt, 1873. A. Operculum, X 85. B. Man- 



dible with muscles, X 85. C. Mandible, X 85 127 



26. Metrarabdotos unguiculatum, new species. Mandible, X 85, of oral 



avicularium with two bundles of muscular fibers 129 



27. Hippaliosina rostrigera Smitt, 1873. A-C. Different forms of the 



setiform mandible of the avicularium. D, E. Opercula, X 85 130 



28. Tremoschizodina lata Smitt, 1873. A. Operculum of ordinary zooecia, 



X 85. B. Operculum of oviceUed zooecia, X 85 131 



29. Mastigophora porosa Smitt, 1873. A, B. SmaU and large opercula, 



X 85. C. Setiform mandible, X 85 134 



