POLYCHAETOUS ANNELIDS FROM CHINA — TREADWELL 273 



podium. The neiiropodium has a conical presetal and two rounded 

 postsetal lobes and a single acicula. There is one sharp-pointed 

 ventral lip much like those of the notopodium in outline and a ventral 

 cirrus reaching nearly to the end of the lip. 



There are three kinds of compound setae. The first have very 

 slender terminal joints that are faintly serrated along the slightly 

 curved border; the second (fig. 19, have short terminal joints bluntly 

 rounded at the ends and without teeth; and the third, stout setae 

 found only in the notopodium, have the terminal joint inserted in a 

 notch in the end of the basal (fig. 19, m). 



The paragnath arrangement is: I, 1 very dark tooth; II, irregular 

 groupings of 2 or more; III, a transverse group of 15 or so, the outer 

 ends of each group being wider than in the middle; IV, a single irregu- 

 lar row; V, absent; VI, a rounded patch of 6 to 8; VII and VIII, 

 together a rather broad irregular patch with a single row of larger 

 paragnaths anterior to the others. 



Type.— V.S.'NM. no. 20117 (Chen no. 31). 



NEREIS (LEPTONEREIS) DISTORTA, new species 



A single male specimen in the epitokous phase. The bodj^ is not 

 complete, but from the small size of the posterior end of the fragment 

 it appears that not much has been lost. It is 70 mm long, with a 

 diamxCter of 8 mm at the seventh parapodium. This diameter is 

 retained for about 15 somites, and then there is a gradual decrease in 

 width toward the posterior end. The prostomial width is 2 mm, the 

 peristomial 3.5 nmi. The three somites follov/ing the peristomium are 

 scarcely wider than it and are very short (fig. 20, a). From the 

 fourth to the eighth setigerous somites there is a rapid increase in 

 length and breadth, the eighth being two and a half times the width 

 and three to four times the length of the peristomium. Possibly some 

 of these differences are due to distortion caused by preservation 

 methods. 



The prostomium (fig. 20, a) is wider than long, with prominent 

 eyes of which the anterior pair are more than twice as large as the 

 posterior and have lenses pointed anterolaterally. The posterior 

 e3^es are distant by about their own diameter from the anterior, 

 and their lenses point dorsally. The posterior margin of the prosto- 

 mium is overlapped dorsally by the peristomium, which in the specimen 

 partly covers the eyes. In figure 20, a, this is drawn as if turned 

 back. The posterior margin of the prostomium is straight and its 

 lateral angles rounded. It is widest just in front of the anterior 

 eyes and then narrows by about the eye diameters. It is rounded 

 anteriorly and divided into two parts by a definite but not very deep 

 dorsal longitudinal incision and an anterior marginal invagination. 

 The tentacles are conical, colorless, about one-eighth as long as the 



