Science Bulletin Volume 1

Science Bulletin Volume 1

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1902 edition. Excerpt: ...however, I shall be able to draw some comparisons between the two families. Eventually I hope to complete such a comparative study of all the Orthopteran families. Material for this larger investigation is now partially on hand, and is being added to as circumstances permit, so that it may be possible to carry through a study of the maturation stages in this order of insects within a few years. The value of comparative cytological study was urged by Vom Rath (25), and its importance in relation to the accessory chromosome and the maturation mitoses received recognition in both my earlier papers (16, 17). Recently Montgomery (15) has added his influence to the movement. The observations upon which the present paper are based were originally made upon Xiphidium. The cells in this genus are, unfortunately, small in size, and much difiiculty was experienced during the early work in getting clear images. This embarrassment was further increased by the large number of chromosomes and their habit of compact arrangement. Later it was found that species of Anabrus, Orchesticus, llficrocentra and Scudderia have cells much better adapted for study, and because of this they have been largely utilized. The account which follows is therefore based upon a study of all these genera, and is considered representative of the family. The accompanying figures are principally from Orchesticus, since the number of stages represented exceeded those in material derived from other genera. I am indebted to a friend and former student, Mr. W. S. Sutton, now of Columbia University, for a generous supply of Orchesticus and Anabrus testes from his collections. II. TECHNICAL METHODS. For the fixation of material used in these studies, it has been found that the more

Product details

  • Paperback | 100 pages
  • 189 x 246 x 5mm | 195g
  • United States
  • English
  • black & white illustrations
  • 1236761073
  • 9781236761071