142 



SYSTEMATIC ZOOLOGY 



£ -An 



FlG. 134. neapolitanus, one of the Archi-Annelida. A, entire animal, dorsal 



aspect, enlarged five diameters; B, anterior end, lateral aspect; (/.anterior end, ventral 

 aspect; D, portion of body showing the metameres; E, posterior end, ventral aspect. An, 

 anus; An.seg, anal segment; c.p, ciliated pit ; gr, grooves between metameres; Mt/i, mouth ; 

 M/mr , metameres ; />, papilla" ; per. st, peristomium ; pr. st, prostomium ; s, setae on tentai 

 /, tentacles. (Aftei r i-aipont, from Parker and Haswell's Text-book.) 



CLASS II. GEPHYREA 



The Gephyrea (Gr. yecfyupa, bridge) are classified with the 

 Annelida, although they exhibit no segmentation, either external 

 or internal. They are all marine worms, widely distributed, and 

 live in the sand or in cavities in the rocks. They are capa- 

 ble of only a slow, creeping movement. The body is more or 

 less cylindrical (Fig. 135) and without parapodia, while in a 

 tew cases there is a small number of setae present. 



The mouth is at the anterior end of the body, sometimes at 

 the base of a shorter or longer proboscis. In the case of the 

 bright green Boucllia viridis the elliptical body of the female 

 is from five to eight centimeters long, while the proboscis is 



