. Quarterly journal of microscopical science. teral Appendages or Limbs ofArthropoda.—It has taken some time to obtain any generalacceptance of the view that the parapodia of the Chfetopodaand the limbs of Arthropoda are genetically identical struc-tures; yet if we compare the parapodium of Tomopteris or ofPhyllodoce with one of the foliaceous limbs of Branchipnsor Apus the correspondences of the two aie striking. Anerroneous view of the fundamental morphology of the crus-tacean limb, and consequently of that of other Arthropoda,came into favour owing to the acceptance of the highlymodified li
. Quarterly journal of microscopical science. teral Appendages or Limbs ofArthropoda.—It has taken some time to obtain any generalacceptance of the view that the parapodia of the Chfetopodaand the limbs of Arthropoda are genetically identical struc-tures; yet if we compare the parapodium of Tomopteris or ofPhyllodoce with one of the foliaceous limbs of Branchipnsor Apus the correspondences of the two aie striking. Anerroneous view of the fundamental morphology of the crus-tacean limb, and consequently of that of other Arthropoda,came into favour owing to the acceptance of the highlymodified limbs of Astacus as typical. Protopodite, endopodite,exopodite, and epipodite weie considered to be the morpho-logical units of the crustacean limb. Lankester (5) hasshown (and his views have been accepted by ProfessorsKorschelt and Heider in their treatise on Embryology ) 552 E. BAY LANKESTEB. that the limb of the Lowest Crustacea, such as Apus, consistso£ a corm or axis which may he joiuted^ and gives rise to out- FiG. 7. Fig. 8. p^p^p^pi. Fig. 7.—Diagram of the somite-appeiidape or parapodium of aPolyclipete ClisEtopod. The cliaeta: are onikted. Ax, the axis ;nr. c, neuropodial cirrlius; nr. U, nr. l^, neurojjodial lobes or endites;nt. c, uotojiodial cirrlius ; ni. l\ nt. P, notopodial lobes or parapodium is represented with its neural or ventral surfaceuppermost, (Original.) Fig. 8.—Three somite-appendages or parapodia of Peri pat , a walking leg ; p to p\ the characteristic pads;/, the foot;cl^, cP, the two claws; B, an oral ])apilla, one of the second pair ofpost-oral appendages ; C, one of the first post-oral pair of appendagesor mandibles; cl\ cP, tiic greatly enlarged claws. (Compare A.) Tlie apjiendages arc represented with the neural or ventralsurface uppermost. (Orij,inal.) growths, either leaf-like or filiform, on its inner and outermargins (endites and exites). Such a corm (see figs. 9 and10), with its outgrowths, may be compared to the simple
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