J 56 My. B. B. AVoodwai-a oii the 



as well as at tlic R\)ex of the antenna, a few very mn;'li 

 smaller hair-like structures somewhat similar to those to 

 "uhieh an olfactory function has been usually ascribed. One 

 of these, in close proximity to the orj^an in question, and two 

 at the apex have a sliape somewhat like that of a hand-bell. 

 The remaining two at the apex are more or le«s cylindrical, 

 with rather blunt extremities. Another on the third segment 

 is shorter and broader and seems to have the form of a trun- 

 cated cone. 



It may be mentioned, in conclusion, that the presence of 

 the " appendix " is not confined to the larvte of a few 

 genera of beetles. According to the observations of Schiodte 

 and of Chapuis and Cand^ze it seems to be characteristic 

 of the larvffi of Carabidaj, of Chrysomelida?, and of certain 

 other large families of Coleoptera, and that, though usually 

 placed towards the outer or posterior side of the distal surface 

 of the penultimate segment, it is, in the Staphylinida3, situated 

 on the anterior side. 



The only other species in which I have had an opportu- 

 nity of examining it was one of Telephorus, in which it had 

 the same relation and pretty much the same general structure 

 as in PterostichuSj the chief difterence being that the chitinous 

 ring, instead of having a uniform width throughout, is narrow 

 at one side and extends upwards, to reach its greatest width 

 on the op]X)site side. It was lirst noticed in this larva by the 

 late G. K. Waterhouse, who referred to it as a '' process." 



Considering, therefore, the widespread existence of this 

 appendix amongst Coleopterous larvae, and of its very definite 

 localization on the penultimate segment of the antennas, 

 together with its rather peculiar structure, it seemed to me 

 that some elucidation of its precise nature and meaning was 

 desirable. And even should it ultimately be proved that I 

 have been mistaken in my first observations upon it, there 

 will be some justification for having directed attention to a 

 structure which seems to have been hitherto almost entirely 

 neglected. 



XX. — Classification of the Pelecypoda: Fisclier's Families 

 rearranged in accordance viilh Pelseneer^ s Scheme. By B. B. 

 Woodward, F.G.S., F.K.M.S., of the British Museum 

 (Natural History). 



The classification of the Pelecypoda has been from the first a 

 matter of great difficulty owing to their comparatively uniform 

 structure. 



The cliaractcrs hitherto employed have been more or less 



