The Arenicolidce of South Africa. 25 



the Zoological Department of the Naturhistorisches Hofmuseum in 

 Vienna, for the loan of the specimen from Angra Pequeua, and beg 

 to thank him for sending it to me. I have thoroughly re-examined 

 this example in the light of recent extensive experience of the two 

 species above named and do not hesitate to state that it is not an 

 example of A. claparedii but of A. assimilis var. affinis. The dorsal 

 region of the oesophageal connectives was very carefully examined 

 with the binocular microscope with the result that no trace of 

 a statocyst could be seen on one side, and on the other its presence 

 was doubtful. A stained and cleared preparation of the peristomial 

 wall, examined with a higher magnification, shows, however, that a 

 statocyst is present, although it is imperfect and recognisable only 

 with great difficulty. Partial maceration of the anterior end has 

 resulted in the disappearance of a portion of the wall of the vesicle, 

 permitting the statoliths to fall out ; the remaining portions of the 

 wall, the cells of which are in a loosely attached condition, stain 

 unsatisfactorily, and are easily overlooked. The presence of 

 nineteen chaetigerous segments, thirteen pairs of gills, short 

 neuropodia, multiple oesophageal glands, and the absence of septal 

 pouches are characters shared only by A. claparedii and A. assimilis 

 var. affinis. The presence of statocysts shows that the worm must 

 be referred to the latter, for A. claparedii does not possess these 

 organs. An examination of the crotchets :;: confirms this diagnosis. 

 The records from Angra Pequeua of A. marina by Professor von 

 Marenzeller and of A. claparedii by the writer must therefore be 

 transferred to A. assimilis var. affinis. 



THE UNIVERSITY OF EDINBURGH. 

 December 22, 1910. 



* See footnote p. 24. 



