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Show 1897.] ON REGENERATION OF THE LEGS IN THE BLATTIDJE. 903 wounds and other injuries, that Mr. Holding thought the specimen exhibited was of some interest as indicating that organic disease might also be a factor in the degeneration of horns. The following papers were read :- 1. On the Begeneration of the Legs in the Blattidce. By H. H. B R I N D L E Y , M.A., St. John's College. Cambridge1. [Received September 13, 1897.] In 1892 Mr. Bateson called my attention to the fact that specimens of the common Cockroach (Stglopyga orientalis) are not unfrequeiitly found to exhibit an abnormal condition of the tarsus, or distal portion of one or more of the walking-legs. This abnormal condition is a numerical variation of the tarsal joints, only four being present instead of the normal number, five-the tarsus as a whole, however, presenting in other respects the features proper to the five-jointed or normal condition. Mr. Bateson suggested to me that it might be worth while to investigate in detail this instance of meristic variation. The particular interest of the case was that the inspection of four-jointed tarsi in a few individuals seemed to point to the conclusion that the relative proportions of the several joints therein were constant. This abnormal tarsus seemed to possess a fixity or organic stability of structure such as is held usually to be the outcome of the continued operation of selection, an influence which can hardly be called upon to account for the condition of an occasional abnormality. The investigation thus originated called attention to facts other than those bearing directly on the original question concerning which information was sought. The latter have been discussed by Mr. Bateson in his work on Variation 2. I postpone reference to his conclusions till an account has been given of the observations made before and after his book was published. The present paper is concerned chiefly with certain facts regarding the reproduction of lost or injured legs in the Blattida;, and with some points in the post-embryonic development of Stylopyga orientalis. The former of these two subjects cannot be considered apart from that of the reproduction of parts among other Insecta and the Arthropoda as a whole. It bas therefore seemed more satisfactory to describe separately the results of the observations and experiments originally undertaken for a more circumscribed purpose, leaving the details of reproduction to a future communication. The leg of the Cockroach resembles that of other Orthoptera, and consists of the following parts : a massive coxa, which is movably articulated with a small trochanter, to which latter is immovably fused a stout femur. The parts distal to the femur are tbe tibia and tarsus, all of whose articulations are movable. 1 Communicated by W . BATESON, M.A., F.R.S., F.Z.S. 2 ' Materials for the Study of Variation,' 1894, pp. 63 & 415. |