Slide showing two diagrams, 'A' - 'Trochosphere of Nephthys', and 'B' - 'Larva of Spio'. Slide shows two diagrams, 'A' - 'Trochosphere of Nephthys', and 'B' - 'Larva of Spio'. Diagrams 'A' and 'B' have further labelling which is explained in the key. Title below images reads:' Fig. 145. - A, Trochosphere of Nephthys. x 65. a, Anus; b, apical plate (brain); c, apical tuft of cilia; c', girdle of cilia; i, intestine; m, mouth; st, stomach. B, Larva of Spiom with three segments , eight days old. x 100. c, Preoral girdle of cilia; c' preanal girdle; ch, long provisional chaetae; pr, prostomium with eyes. (From Chaparede and Metschnikoff.)' Late 19th to early 20th century