Electron microscopical investigations on two loricate choanoflagellates (Choanoflagellida), Calotheca alata gen. et. sp. nov. and Syndetophyllum pulchellum gen. et comb. nov., from Indo-Pacific localities. Proceedings Royal Society of London Series B Biological Sciences, 219(1214) 1983: 41-52. 43 [Zoological Record Volume 120]