326 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



membrane. The latter shows a thin area through which 

 later the larva forces its way. x 210. 



Fig. 75. Larva three days (72 hours) after fertilisa- 

 tion of the egg. Dorsal aspect. Both ciliated bands are 

 now present, and there are two eyes on the prostomium. 

 Ten minutes after the drawing was made the larva forced 

 its way through the thin area in the upper portion of the 

 vitelline membrane, x 210. 



Fig. 76. Larva one day after hatching. Dorsal 

 aspect. Two short spade-shaped setae are present. The 

 anterior and posterior ciliated bands and the eyes are also 

 shown. The specimen was slightly compressed by the 

 cover-glass and therefore appears a little broader than it 

 should be. x 210. 



Fig. 77. Larva twelve days after hatching. Seen 

 from the right side. The prostomium bears two eyes and 

 several small groups of sense hairs. Setae are present in 

 three segments, in the first two of which both notopodial 

 and neuropodial setae may be seen. The notopodial setse 

 are of two kinds. The alimentary canal is complete from 

 mouth to anus, the middle portion is dilated with yolk. 

 The coelom is oibvious post-orally. The anterior girdle of 

 cilia has entirely, and the posterior one almost, disappeared. 

 The anterior portion of the ventral band of cilia still 

 remains. x 210. 



Fig. 78. A (notopodial) seta from the larva shown in 

 fig. 76. x 1000. 



Fig. 79. Two setae from the larva shown in fig. 77. 



Fig. 79 A, One of the neuropodial crotchets. The 

 dotted line indicates the level of the epidermis. x 1000. 



Fig. 79B. The distal portion of one of the notopodial 

 setae. The other seta in the same notopodium is similar 

 to the one shown in fig. 78. x 1000. 



