Arenicola branchiahs 143 



not uncommonly in examples of A. grubii. There is therefore no 

 character by which A. branchialis, as described by Audouin and 

 Edwards, can be distinguished from the examples of A. yrubii above 

 mentioned. 1 These two species are therefore merged under the earlier 

 name branchialis. 



Prof. Mesnil considered A. branchialis and A. grubii to be 

 identical, and advocated a return to the former name for this species. 

 He suggested that Audouin and Edwards had counted and figured an 

 anterior abranchiate segment too many, and thus assigned the gills 

 to a position one segment too far back. The writer cannot see any 

 evidence of this in the figure, which represents the segmentation of 

 the anterior end approximately accurately, and considers it much 

 more probable that in Audouin and Edwards' specimen the anterior 

 gills were wanting, as in that described above. 



OBSERVATIONS ON THE EECOKDS. Chenu's modification of the 

 original figure by the addition of a tail as long as the branchial 

 region was unwarrantable, and shows that his figure, instead of being 

 from nature, was a composition. Gosse placed his specimen near 

 A. branchialis, probably because the number of branchiate segments 

 was not the same as in Audouin and Edwards', but it was evidently 

 of this species. The five following citations refer to descriptions 

 which include both caudate species under the name A. branchialis 

 (see also p. 135). 



The three species described by Czerniavsky from the Black Sea 

 all possessed the eleven anterior abranchiate segments characteristic 

 of A. branchialis, and differed from one another only in colour and in 

 the number of branchiate segments, of which they had twenty, 

 thirteen and fifteen respectively. The type specimen of A. bobretzkii 

 is no longer in existence, but the writer has had a dozen examples 

 from the same locality the Bay of Sevastopol all of which are 

 A. branchialis. By the courtesy of Prof. Nassonow the author has 

 been enabled to examine the types of A. cyanea 2 (= cyaneus) and 

 dioscurica, which are preserved in the Zoological Museum of the 



1 The writer has reached this conclusion only recently, and after examining 

 a long series of specimens, in which he found the examples cited above with 

 reduced gills and those with the terminal region more elongate than usual. 

 When PI. II was printed, early in 1909, he was of opinion that the 

 identity of A. branchialis and grubii could not be established with certainty, 

 and that therefore the correct name of the species was A. grubii. 



2 The much inflated anterior ring, mentioned in Czerniavsky's description 

 of this species, is the protruded pharynx. 



