"Cross-section of Arenicola. E., Epidermis; c.m., circular muscles; l.m., longitudinal muscles; b.c.,…
"Cross-section through Ascaris. d.n., Dorsal nerve; n.c., non-contractile portion of muscle cells; c.,…
"Dissection of lob-worm from dorsal surface. m., Opening of retracted buccal cavity; i., gullet; gl.,…