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Show 4 DR. P. PELSKNEER O N T H E COXAL [Jan. 20, During the month of October 1884 a large living Mygale {Thera-phosa), from South America, was placed by the Secretary of the Zoological Society of London at the disposal of Prof. Lankester, who had the kindness to entrust it to me in order that I might make out the position of the coxal gland. He gave me at the same time the series of transverse sections of the cephalothorax of Mygale ccementaria, which he had made at an earlier date. Having carefully studied the latter, I drew those which passed through the coxal gland, whenever this presented any change of shape, size, or position. One of the sections in which the gland presents its greatest development is shown in Plate II. fig. 1. By the help of this series of drawings I was able to construct two diagrams, one of which showed the vertical projection (view from the" side) of the gland, the other the horizontal projection (view from above). The latter is shown in Plate II. fig. 2. In his recent paper l Prof. Lankester expressed the expectation, after examining sections of a South-American Mygale, that the coxal gland was not a simple ovoid glandular body, as in Scorpio, but that it was furnished with lobes corresponding to the coxae of the cephalothoracic appendages, as in Limulus. The figure shows how well founded this anticipation was. Taking these two diagrams as my guide, I looked for the coxal gland of the large Mygale, which was still pretty fresh, as it had only Iain for a few days in 60 per-cent. alcohol, having been opened and washed with normal salt solution (| per cent.) after being killed, and I was able to dissect it out completely. The two glands, which are quite separate, are placed on each side of the cephalothorax, at the side of the entosternite (enthodere of Duges), between the lower plate and the upwTard prolongations of it, to which latter they are intimately related in position, size, and form 2. Surrounded by the connective tissue with large brown cells, which is found scattered through the entire body of Mygale \ they extend as far as the edge of the lower plate of the entosternite, and have four lobes which correspond to the projections of this plate and at the same time to the four last appendages of the cephalothorax (ambulatory legs) 4. The anterior and posterior lobes of the gland are the largest, and are parallel in direction to the long axis of the body. The second and section of Mygale javanensis, Walk., given by Lienard, "Eecherches snr la structure do 1'appareil digestif drs Mygales et des Nephiles," fig. 2 A (Bull. Acad. Belg. 1878). The ghmd is shown under the upper part of the diverticulum of the stomach, between its bend and the entosternite. 1 Loo. cit. p. 52. 2 The relations between the entosternite and the coxal glands are the same in Limulus and Scorpio as in Mygale, as is easily seen from the works published on this subject. 3 This tissue is analogous to that observed in Scorpio by Prof. Lnnkester {loc. cit. pi. xi. figs. 9-10), but the cells are larger, fewer in number and more scattered. 4 And not to the second, third, fourth, and fifth appendages, as in Limulus |