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Show 204 MR. F. E. BEDDARD ON THE STRUCTURE [Mar. 5, The genital papilla} are, as figured by Bourne, four pairs. He does not mention, however, certain slight differences in the position of the different pairs. The first pair, i. e., those lying between segments xv./xvi., and the last two pairs correspond in position to the outermost of the two ventral setae ; that is to say, a line drawn from this seta would pass through the middle of the papilla. On the other hand, the second pair lie between the two setae of the ventral couple. As Bourne states, the two anterior pairs of papillae are much more marked than the two posterior pairs. I find the position of the oviducal pores rather different from that illustrated by Bourne. Each lies in front of the inner seta of the ventral couple ; it is noteworthy, perhaps-in connection with the remarks that I have made above concerning the asymmetry of the oviducal pores of T. nicholsoni-that in the present species the left-hand pore is decidedly the larger. The excellent condition of preservation of m y specimen enables me to add a few details to our knowledge of the internal anatomy of this species. I find that the arraugement of the septa is a little different from that described by Bourne. The first plainly recognizable septum, which is also fairly thick, separates segments v. and vi. Then follows a much stouter septum, which limits anteriorly segment vii., in which segment lie the spermathecae. Behind the sperma-theca and attached to the anterior end of the gizzard is a thin and delicate septum. The gizzard therefore occupies segment viii. It is followed by three thickened septa, to the first of which it is attached by two symmetrically placed strap-shaped bands of muscle. The position of some of the organs of the body is a little difficult to ascertain, and appears to vary from what I have described above in T. nicholsoni. I believe Bourne to be right in placing the anterior end of the sperm-sacs in segment xi.; they extend back to xiii. There is, however, no real anomaly inasmuch as these sacs are not attached to septum x./xi.; they may be considered to belong morphologically to segment xii., from which they have grown forwards as well as backwards. The calciferous glands I should place iu segment xii. The last hearts are in xiii. I find five pairs of intestiual glands-not four as Bourne has stated ; they are bilobed, the furrow being transverse. The several species of the genus Typhoeus show a very considerable uniformity of internal structure, combined with a marked variation in the numbers and the arrangement of the genital papillae. U n fortunately data are wanting as to the internal structure of Typhoeus leevis, and several details of importance from a systematic point of view have been left undescribed by myself in T. orientalis, which, however, as the first known species of the genus was amply characterized as such. The only real difference in the internal structure which can be deduced from our present knowledge is the |