344 LIVERPOOL MARINE BIOLOGY COMMITTEE REPORT. 



Annelides Polychetes des Mers de la Nouvelle-Z&nihle."' 

 As is pointed out by Bourne {loc. cit.), the shape of the 

 parapodia is variable in one and the same individual, and 

 equivalent parapodia must in all cases be compared. At 

 the same time, even then the normal shape of the parapodia 

 may be altered by the presence of eggs in the body cavity, 

 the amount of retraction of the acicula, and the condition 

 of the caeca of the alimentary canal. The general appear- 

 ance, the number of segments, and a typical transverse 

 section require to be more attended to than they are ; the 

 merest outline of the form, natural size, with any striking 

 character, seems an accompaniment to a description of new 

 or rare species very much needed. 



Since writing the above, I have been glad to find my 

 opinion supported by Hansen, in his Keport on the Anne- 

 lides of the Norwegian North Atlantic Expedition.! I quote 

 the sentences more especially bearing on the point in ques- 

 tion. After pointing out that Malmgren has attached espe- 

 cial weight to the distinctive features of the pedal bristles, 

 considering them, indeed, as of generic value, he goes on to 

 say :— 



" From what is stated here, a considerable difference might be 

 inferred to exist between the members of the family Polynoidce, and 

 not only as concerns the structure of the bristles, but also with regard 

 to the external anatomical features of the animals. This, however, is 

 not the case, as will at once appear from a glance at Malmgren's own 

 drawings. Indeed, unless carefully examined in detail, it is hardly 

 possible to distinguish between them, so closely do the animals 

 resemble one another. . . . The last feature to adduce as a generic 

 character would be, if justly considered, the structure of the bristles, 

 which are so remarkably alike in well-nigh all Polynoce that very con- 

 siderable difficulty is frequently experienced in distinguishing between 



* Kongl. Svenska. Vetenskaps-Akademiens Handling ar, Bandet xvi, 

 No. 3, 1879. 



f Den Norske Nordhavs-Expedition, 1876-78, Zoologi, Annelida, ved 

 G. Armauer Hansen, 1882. 



