Arenicola marina 95 



include representatives of two other species, namely, A. pusilla (from 

 Vancouver) and A. assimilis var. affinis (from Angra Pequeiia). 



Leach defined A. carbonaria as having "body, coal black." The 

 specimen, which was found near Leith, is doubtless that in the 

 British Museum Collection labelled "Arenicola carlonaria. Black 

 Eock, Frith of Forth. Mus. Leach." This is a very dark example 

 of A. marina (cf. PL I, Fig. 3). 



Eanzani based his species Arenicola clavatus on three specimens 

 in the Museum of the LTniversity of Bologna. 1 The place of origin of 

 the specimens 2 was unknown. Eanzani distinguished his new species 

 from A. piscatorum, as described by Pallas and Cuvier, because the 

 anterior region was inflated and thicker than the middle region, the 

 tail was long and " articulated," and the gills black. The dilatation 

 of the anterior portion, due to the forward rush of the coelomic 

 fluid, and the articulation of the tail, caused by strong contraction of 

 some of the circular muscles, are features of no specific value ; they 

 are seen in many specimens of A. marina which have been killed 

 quickly in alcohol. The specimen figured by Eanzani was about 

 217 mm. long, so that, if from the Adriatic or any other European 

 source, it is certain to have been an example of A. marina, as the 

 other externally similar European species A. pusilla attains only 

 about half this length. A. clavatus may therefore be safely merged 

 with A. marina. 



The specimens 3 on which Girard founded the species A. natalis 

 were shortly and insufficiently described. Nevertheless, it is certain 

 that they were ordinary examples of A. marina. It is evident that 

 Girard mistook the ventral for the dorsal surface, as he stated that 

 the dorsal region was marked by a conspicuous smooth line, dividing 

 on the cephalic region into right and left branches, which united 

 anteriorly. This smooth line, the dorsal position of which was given 

 as one of the specific characters, is, however, mid- ventral : it marks 

 the position of the nerve-cord, and is seen in all specimens of 

 A. marina. The other distinguishing features of A. natalis the 



1 During a visit to that Museum the writer made inquiry for Ranzani's 

 specimens, and careful, but unsuccessful, search was made for them ; they are 

 no longer preserved. 



2 Oken (Isis (1817), 1452), but without stating his grounds, said that they 

 came from the Adriatic. The writer has examples of A. marina from Trieste, 

 which agree closely in size and appearance with those described by Ranzani. 



3 The specimens have apparently not been preserved. The Curator of the 

 Boston Society of Natural History stated, in answer to the writer's inquiries, 

 that he had not been able to locate the type of A. natalis, and that there was 

 no record of its having been given to the Society. 



