NO. 1772. ANNELIDS OF THE ARENICOLTD.^—ASHWORTH. 13 



number 91); there is another, doubtless from the same batch, in the 

 Museum of the Zoological Institute, Gottingen (no. 27a). In four 

 of those in the Harvard collection and in the Gottingen example the 

 seventh segment is abranchiate, the first gill being borne on the eighth 

 segment ; the fifth Harvard specimen has a pair of very small gills on 

 the seventh segment. These specimens vary in length from 105 mm. 

 (of which the tail forms 13 mm.) to 207 mm. The tail of the latter 

 specimen reaches the extraordinary proportion of 117 mm. 



A specimen from Puget Sound, from the collection of H. P. John- 

 son, is preserved in the Harvard Museum (no. 956) and another is in 

 the Department of Biology, University of California (no. 1066). The 

 former is 94 mm. and the latter 60 mm. long, of which in each case 

 the tail forms 13 to 14 mm., but the posterior end is apparently 

 incomplete in both cases. In both these and in two other specimens 

 from the same collection, given to me by Doctor Johnson, the first 

 gill is borne by the seventh segment, but in one specimen there is a 

 gill only on the right side of that segment, the corresponding gill of 

 the left side being absent. 



There are examples of this species in the Smithsonian Collection 

 from Constantine Harbor, Amchitka Island, Aleutian Islands (1047); 

 Atka Island, Aleutian Islands (no number); Sand Point, Humboldt 

 Bay, California (no number). 



The single specimen from Humboldt Bay, the one from Amchitka 

 Island, and one of the four from Atka Island were opened in order to 

 see the internal organs. All are typical examples of the species in 

 regard to both their external and internal features, prostomium, 

 neuropodia, nephridia, oesophageal glands, absence of septal pouches; 

 statocysts could not be found on dissection of the anterior region of 

 these specimens. In the case of the dissected specimen from Atka 

 Island, the region in which the right statocyst is situated in those 

 species which possess these organs, was excised and cut into serial 

 sections, an examination of which proves that a statocyst is not 

 present in this worm. 



I have recently examined seven specimens from Dutch Harbor, 

 Unalaska (Harriman Expedition), and a dozen specimens collected 

 at San Juan Island, in the Strait of Juan de Fuca. All are typical 

 examples of A. claparedii, and in all the first true gill is present. 

 The absence of statocysts was determined in a large specimen from 

 Unalaska by dissection, and in the case of those from San Juan by 

 examination of serial sections of the anterior end of one of the worms. 



The specimens from Unalaska are the largest examples of this 

 species I have seen. Their length, 132 to 160 mm., is not specially 

 remarkable, but they are of massive build, the four largest specimens 

 have a girth (measured at the fifth segment) of 50 to 60 mm. 



