118 



Arenicolidae 



nuchal organ. There are six pairs of nephridia, opening on the fourth to 

 ninth segments, twelve oesophageal glands, six on each side, and no 

 septal pouches. Careful search failed to reveal the presence of stato- 



L. 



M.GR. 



N.GR. 



Mo. 



-Nor. 



Fig. 51. Fig. 52. 



Figs. 51, 52. A. pusilla. Type specimen, antero-vcntral (Fig. 51) and dorsal (Fig. 52) views of the 

 anterior end. In Fig. 51 all the parts, except the prostomium, are seen somewhat fore-shortened. 

 L, Lateral lobe of prostomium ; M, Median lobe ; M.GR, Metastomial groove ; Mo, Mouth ; 

 N.GR, Nuchal groove ; NOTI, First notopodium ; P, Median posterior portion of prostomium. 



cysts, and the writer believes them to be absent. 1 The type was 

 compared directly, point by point, with a long series of examples of 



N.GR. 



M.GR. 



PER. 



1--A.B.S. 



Fig. 53. Fig. 54. 



Figs. 53, 54. A. pusilla. Specimen from California, antero-ventral (Fig. '53) and dorsal (Fig. 54) 

 views of the anterior end, for comparison with Figs. 51, 52. PER, Peristomium ; A.B.S, 

 Achaetous body-segment (note the strongly developed groove between these segments, see p. 37). 



A. claparedii. The anterior end of one of these, from Crescent City, 

 California, is represented in Figs. 53, 54, which show that, making due 



1 To establish, beyond doubt, the absence of statocysts, it would be necessary 

 to make serial sections of the anterior end, a course which is obviously precluded 

 in this case. 



