Calpidium ponderosum, Goldst., sp. Aldinga. 



Cellularia cuspidata, Busk. Encounter Bay. 



Scrupocellaria scrupea, Busk. Encounter Bay. 



Menijjea crystallina, Busk, sp. Robe. 



Bugida cucullata. Busk. Lacepede Bay. 



B. dentata, Lamx. Robe. 



B. neritina, Linn., sp. Brighton. 



Carhasea pisciforinis, Busk. Kangaroo Island. 



Flustra denticulata^ Busk. Encounter Bay. 



Electra flagellum, McG. Brighton. 



Thairopora Woodsii, McG. Semaphore. 



T. Jervoisii, Hincks, sp. Brighton. 



Cribrilina monoceros, Busk. Brighton. 



Schizoporella schizostoma, McG. Brighton. 



Mucronella Mlerii, McG. Glenelg. 



Sinittia trispinosa, Johnston, sp. Brighton ; Semaphore. 



EXPLANATION OF PLATE I. 



Fig. 1. Memhranipora prcelonga, X 20. 



Fig. 2. Biflustra jugcdis, group of zocecia x 45. Fig. 2a. Single zooecium, 



showing the oral flap, x 45. 

 Fig. 3. Schizoporella Smeatoni, x 45, showing zooecia and ooecium. Fig. 



3a. Operculum, x 100. 

 Fig. 4. Schizoporella Maplestoni, normal form, X 45. 

 Fig. 5. Id, var. avicularis, showing suboral avicularium and thickening of 



peristome in ordinary zocecia. Fig. 5a, Another zocecium and ooecium 



from the same specimen. All x 45. 



