NEMERTINA. 81 



in front, pointed behind ; with the margins rolled 

 up together ; eyes none. 



C. paradoxa. Fig. 127 ; LO. 



Order II. CESTOIDEA. 



iouth below ; vent terminal .... 



/"ent below ; mouth terminal .... Serpentariana. 



TRIBE I. NEMERTINA. 



Astemma (Oerst). Body linear, roundish ; eyes 

 none ; mouth not remote from the extremity. 



A. rufifrons. Fig. 128 ; n. s., and head and proboscis, mag. 



Tetrastemma (Ehr.). Body linear, or linear- 

 oblong ; respiratory fissures indistinct ; eyes four. 



T. quadrioculatum. Fig. 129 ; n. s. and head mag. 



Polystemma (Ehr.), Body linear, sub-depressed ; 

 eyes numerous, in two or four groups ; fissures in- 

 distinct ; two red spots (translucent hearts) in the 

 neck. 



P. roseum. Fig. 130 ; n. s. and head mag. 

 pulchrum. 

 gracile. 

 armatum. 

 album. 



Nemertes (Cuv.). Body roundish, linear; head 

 and fissures distinct ; eyes four to fourteen, in two 

 groups. 



