. Zoology : for students and general readers . Zoology. i74 ZOOLOGY. rim inside. Two of the ten arms arise from the under side of the licad ; they are twice the length of the eight others, and oval at the end. On each side of the head behind the tentacles are the remarkably large eyes, which, though usual- ly said to be more like the vertebrate eye than those of any other invertebrate, are really constructed fundamentally on the same plan as the eye of the snail; differing in several important respects from that of a Vertebrate, the resem- blances between the two being superficial, while the s
. Zoology : for students and general readers . Zoology. i74 ZOOLOGY. rim inside. Two of the ten arms arise from the under side of the licad ; they are twice the length of the eight others, and oval at the end. On each side of the head behind the tentacles are the remarkably large eyes, which, though usual- ly said to be more like the vertebrate eye than those of any other invertebrate, are really constructed fundamentally on the same plan as the eye of the snail; differing in several important respects from that of a Vertebrate, the resem- blances between the two being superficial, while the struc- ture of the eyes of mollusks is quite unlike that of Crusta- ceans, insects or Vertebrates. The mantle loosely invests the front of the body next to the head, so that the water piasses in around the neck in order to bathe the gills, which are quite free from the visce- ral mass. The man tie is beau- tifully colored and spotted, the change of color being due to the change in form of the pigment masses or cliromato- jiliores, which are under the influence of the peripheral nerves. The mantle is supported by ; iimie. About a hornv "pen" (Fig. 314), or one third natural size.—After Verrill. "^ t" , i • pen-shaped thin support, ex- tending from the upper side of the anterior edge of the mantle to the end of the l)ody. In the Sepia of the Medi- terranean Sea this is thick, formed of limestone, and is called the " cuttle-fish ; The organs of digestion consist of a mouth, pharynx, cesophagus, stomach and intestine. The mouth is situated. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Packard, A. S. (Alpheus Spring), 1839-1905. New York : Henry Holt
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectzoology, bookyear1879
