Arenicola piisilla 119 



allowance for some contraction of the oral region and compression 

 of the median prostomial lobe, this specimen and A. pusilla have 

 prostomia of an identical type. They agree also in their internal 

 organs, except that in A. claparedii there are typically only five 

 pairs of nephridia ; but this difference is not sufficient to justify 

 the separation of two otherwise identical forms, as it may be an 

 individual or a local variation. 1 The writer two years ago reached 

 the conclusion, which subsequent examination of further material 

 has amply confirmed, that A. pusilla and claparedii are identical, 

 and the two species are therefore merged under the older name. 



OBSERVATIONS ON THE RECORDS. Prof. Child's specimens of "A. 

 marina" were those afterwards examined and recorded by Dr. H. P. 

 Johnson as A. claparedei. The Neapolitan specimens examined by 

 Claparede and Jaquet, and those recorded by Lo Bianco, were 

 examples of A. pusilla ; Jaquet's figures show that several oesophageal 

 glands and five pairs of nephridia were present, and that statocysts 

 were absent characters which apply only to A. pusilla. A. marina 

 does not occur at Naples. 



The two specimens on which Prof. Ehlers' record from Puerto 

 Montt was based, which are in a bad state of preservation, have been 

 carefully examined by the writer. In the number of their segments, 

 the number and position of their gills, in the presence of short 

 neuropodia the only external characters 2 preserved and in the 

 number of oesophageal glands and absence of septal pouches, these 

 specimens agree with A. pusilla and assimilis var. affinis. Statocysts 

 could not be found, although the anterior end of one of the worms 

 was cut into serial sections ; the preservation was, however, so 

 defective that it is possible the statocysts had disappeared owing to 

 maceration. The writer has recorded these specimens as A. claparedii 

 ( = pusilla), and it seems advisable to retain this record with a query, 

 and with the proviso that there is some possibility that the specimens 

 may be A. assimilis var. affinis. 



Prof, von Marenzeller's material of " A. marina " from several 

 localities included specimens from Naples and Vancouver Island. 

 The writer has recently examined one of the Vancouver examples, 



1 Such a variation is seen in the number of nephridia in A. assimilis var. 

 affinis ; examples from South Africa have only five pairs, while those from 

 South America, New Zealand and Tasmania possess six pairs. 



2 The crotchets were worn, and did not serve to decide the identity of the 

 species ; hi their characters they were not typical of A. pusilla, but tended 

 towards those of A. assimilis . 



