NEREIS CULTRIFERA 



177 



prostomium and the peristomium. On the prostomium are situated 

 dorsally a pair of prostomial tentacles and two pairs of eyes, 



Fig. 125. — A transverse section through Nereis cultrifera, shghtly simphfied. The 

 parapodia are shown in perspective. Magnified.— After Shipley and MacBnde, 

 with modifications. 



I, Cuticle; 2, epidermis; 3, circular muscles; 4, longitudinal muscles; 5, obHque muscles forming a 

 partition ; 6. somatic layer of oeritoneal epithelium ; 7, ccelom ; 8, splanchnic layer of epithehum ; 

 9 cavitv of intestine; io, dorsal blood vessel; 11, ventral blood vessel; 12, ventral nerve cord; 

 13, nephridium in section ; 14, ova ; 15, notopodium ; 16, neuropodmm ; 17, dorsal cunrus; 18 ventral 

 cirrus ; 19, cha3t« ; 20, aciculum ; 21, muscles which protrude the acicula and thus the noto- and 

 neuropodium ; 22, ciliated organ (vestige of coelomoduct). 



Fig. 126 —The head of Nereis, with the pharynx protruded. 



Eves • i jaw • p., palp ; pe., peristomium (first two segments fused) ; ph., pharynx ; pp., first ordinary 

 parapodium ; pr., prostomium ; t., accessory teeth ; tc, tentacular cirri ; te., tentacle. 



each of which is a pit Uned by pigmented cells and enclosing a 

 gelatinous mass which serves as a lens. Ventrally the prostomium 

 bears a pair of stout palps. The peristomium carries on each side 



