Microscopical Studies in Marine Zoology (Paperback)

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: a thinning takes place at the apex, and finally gives way to permit of the extrusion of the polypite's tentacles); g, gonotheca; m, medusid buds in different stages, within the gonotheca. Fig. 3. View from below of a freed medusa. Fig. 4. Diagram of same. Fig. 5. Diagrammatic vertical section through same. The section follows the course of a radial canal on the right side, while on the left, an interradial portion of the disc is sectioned. Fig. 6. A Medusa, considerably older than that shown at Fig. 3, seen reverted and from the side. It had just captured an Arrow-worm (Sagitta), which is doubled up, the bend being within the digestive cavity of the Medusa. Lettering the same for Figs. 3?6, viz: ?a, atrium; c.c, circumferential canal; en, endoderm; g.g, genital glands; m, manubrium; o, mouth; ot, otocyst; r.c, radial canal; s.u, sub-umbrella; t, tentacle; u, umbrella; v, velum. Study XII.?On Polynok Propinqua As Typical Of The Higher Annelids. Polynoe propinqua (Malmgren) is an elegant marine annelid, short and slender in its proportions, rapid and lively in its movements. When the tide recedes, its haunts are to be found wherever boulders litter the shore, and many a weary backache have I had through a course of such stone-turning. It is easily recognized by reason of two rows of oval overlapping brownish scales that lie upon its back, and from under which project, oar-like, on either side, serried banks of lovely translucent paddling-bristles. A pretty creature, but loath to be captured. Alarmed at the approach of the forceps, it squirms and makes desperate effort to escape, and indeed if it be lifted roughly and by force, instead of being taken by some gentle snare, lo! it breaks into pieces and is to you but a worthless capture. A cursory examination ...