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Show 1890.] REPETITION OF PARTS IN ANIMALS. 583 Though there is not sufficient evidence for determining the question, it may be mentioned that the general appearance suggests that the double dactylopodite, D, is the normal one of the limb and that the process, P, which is warped over to meet it, is the process normally opposed to it. The process P', which is opposed to the dactylopodite, D', is comparatively small and ill-developed. The class of variation shown by these three specimens is not uncommon amongst Decapoda (cf. Faxon, Leger, &c). In addition to these cases an especially interesting one should be mentioned which was communicated to m e by Mr. G. C. Bourne, Director of the Marine Biological Laboratory. This specimen, which was not seen by myself, was sent to Mr. Bourne by Mr. Dunn of Mevagissey, Cornwall. It was an edible Crab (C. pagurus), measuring about 2*5 inches across. In this specimen the three posterior walking-legs of one side were seen to be each repeated. It had lately moulted and was much decomposed when received. Unfortunately an imperfect examination of it was made and the specimen has been destroyed. Similar occurrences among Crustacea and insects have been recorded by Leger and others. III.-Beetle (Chrysomela banksii) having three complete Tarsi on one Leg. This specimen was kindly lent to m e for description by Dr. Sharp, who obtained it from the JNew Forest. It was exhibited at a meeting of the Entomological Society in 1862, but has not been figured or described in detail. The tibia of the third leg on the right side has the form shown in the figure. Fig. 3. A |.;|^, Ii » A, Abnormal right posterior leg of Chrysomela banksii. B, Normal leg in the some position, from a rather larger specimen (enlarged to scale). (Figures drawn by Mr. Edwin Wilson.) Its outer extremity, which is widened into a flat, club-shaped structure, bears three complete tarsi, each of which is perfect in all its four joints and carries a pair of normal claws. These three tarsi are equal in size, but are very slightly smaller than those of the same leg on the other side. In addition to the three tarsi the tibia is produced into a small horn, which projects from it rigidly, having no articulation. At the |