. On the anatomy of vertebrates. Vertebrates; Anatomy, Comparative; 1866. ANATOMY OF VERTEBRATES. 31 wLiljytjTuce liner ]:iyer -a, 22 outerInyer of flbrous capsule ueural caual fll^rous liantl, or basis of latiuous chorda cylindrical fibrous slieatli, filled with simple cells containing jelly. The centrums, or ' bodies of the vertebra,' are developed in and from the notochord. The leases of the other elements are laid down in fibrous bands, diverging from the notochord, and giving the first indication of the segmental character of the skeleton. In Denitopteri the neu- ral and h;\3mal
. On the anatomy of vertebrates. Vertebrates; Anatomy, Comparative; 1866. ANATOMY OF VERTEBRATES. 31 wLiljytjTuce liner ]:iyer -a, 22 outerInyer of flbrous capsule ueural caual fll^rous liantl, or basis of latiuous chorda cylindrical fibrous slieatli, filled with simple cells containing jelly. The centrums, or ' bodies of the vertebra,' are developed in and from the notochord. The leases of the other elements are laid down in fibrous bands, diverging from the notochord, and giving the first indication of the segmental character of the skeleton. In Denitopteri the neu- ral and h;\3mal canals are formed by a separation of the layers of the outer division of the sheath of ,1 ,1 If. .-^.-i A Transverse vertical sectiou of vertelintl column of JV/'/x/iie. XXI. the notochord, fig. 22. A transverse partition divides the larger portion of the neural canal, lodging the myelon, from a smaller portion above containing adipose tissue. In the Lancelet the substance of the noto- chord, fig. 23, cli, consists of a number of circular discoid or flattened vesicles, p)resscd one upon another within the sheath, like a pile of coins in a purse ; the sheath is strength- ened by a longitudinal filamentary ligament above and below. Apjoneurotic septa jiass off, with each pair of nerves, to the interspaces of the muscular segments, giving attachments to the fibres. A median vertical membrane rises from the neural. riiagram of anatomy of tlic Lancelet, BranclnoUovia sheath, and beyond the abdominal cavity descends from the hasmal sheath, passing between the right and left series of myocommata. The dermo-neural and dermo-hasmal spines are indicated by short linear series of firmly adhering flattened cylindrical cells. The next step in the skeletal tissues is shown in a pair of jointed cartilaginous filaments, fig. 23, /*, which bound or strengthen the borders of the longitudinal oral slit, each cartilage supporting on conical prominences the oral cirri (ib. /, /): numerous carti- l
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Keywords: ., bookauthorowenrichard18041892, bookcentury1800, bookdecade1860
