Bulletin of the Museum of Comparative Zoölogy at Harvard College, in Cambridge, 1891-92

Download or read book Bulletin of the Museum of Comparative Zoölogy at Harvard College, in Cambridge, 1891-92 written by Museum Of Comparative Zoology and published by Forgotten Books. This book was released on 2017-10-19 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Bulletin of the Museum of Comparative Zoölogy at Harvard College, in Cambridge, 1891-92: Vols. XXI and XXII When viewed from above, the general form of the animal is elongated its lateral margins are nearly parallel, being slightly convex posteriorly the widest part of the body is in the pharyngeal region. The largest specimens measure 30 mm. In length by 4 - 5 mm. In breadth. Anteriorly the sides converge slightly up to about the region of the eyes, where the diameter increases, thus forming the' so called head. This bears the lateral auriculate appendages. The lateral appendages are rounded, rather than triangular as described by Leidy they are continuous with, and in fact form part of, the anterior extremity; posteriorly, the sides converge to a point (fig. 20 a). The eyes appear as two elongated oval white spots, with black pigment on the internal edge. They are situated on the narrow part or neck. Haldeman and Leidy have described the head as being straight in front. This appearance is seen only when the animal is at rest. It is then much contracted in the direction of its antero - posterior axis, and is usually much distorted; at such times it often appears as a shapeless black lump, this condition probably being a means of protection (f igs. 20 b and 20 When in motion the anterior extremity is usually convex, but not always, for it may be straight, sinuous, or concave these shapes are only temporary, following each other in quick succession. The head changes its form especially when the animal approaches some object; for this part of the body is functional as an organ of touch that it is suited structurally to be a kind of feeler will be evident from the description of the nervous system which follows. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.