PLATE VII. 



Class PLATYHELMINTHES. 



NEMERTEA. 

 Borlasia and Polia. 



FIG. 1. BORLASIA : HEAD, MIDDLE AND TAIL PORTIONS, x 1. 

 h. head : m. part of the body : t. tail. 



FIG. 2. BORLASIA : ANTERIOR PORTION, VIEWED AS A TRANSPARENT OBJECT. 

 (After Quatrefages.) x 4. 



m. mouth : p. ciliated pit : e. groups of eyes : v. cephalic blood-vessel : 

 c. n. cephalic nerves, given oft 1 from g. cerebral ganglia : n. 

 lateral nerve cord : d. dorsal blood-vessel : /. lateral blood- 

 vessel : pb. proboscis : g. genital organs. 



FIG. 3. POLIA : STYLE-FORMING APPARATUS. (After Quatrefages.) 



p. proboscis: i. intestine: s. stylet: g. gland of the stylet: c 1 . cavity 

 of the completely formed stylet s. : c 2 . cavity containing 

 stylets in process of formation : o. 1 , o. 2 anterior and posterior 

 dilatations of the oesophagus. 



FIG. 4. TRANSVERSE SECTION THROUGH THE ANTERIOR PORTION OF A 

 NEMERTINE (species ?). x 10. 



p. proboscis: s. sheath of the pioboscis: n. lateral nerve cord: 

 o. oesophagus. 



