. Elements of the comparative anatomy of vertebrates. Anatomy, Comparative. 8 COMPARATIVE ANATOMY somatoi>leure, and the latter, together with the hypoblast, the svlanchnovleure. The cavity separating these is the body cavity or coelome (Fig. 1)} and is lined by an epithelium. The dorsal part of the mesoblast which lies on either side of the middle line early becomes transversely segmented to form a series o± mesoUastw somites or protoverteirw, which lose their cavities (Fig. 6, A and ±5} and are concerned in the formation of the vertebral column, body muscles, and urinogenital apparatus. A
. Elements of the comparative anatomy of vertebrates. Anatomy, Comparative. 8 COMPARATIVE ANATOMY somatoi>leure, and the latter, together with the hypoblast, the svlanchnovleure. The cavity separating these is the body cavity or coelome (Fig. 1)} and is lined by an epithelium. The dorsal part of the mesoblast which lies on either side of the middle line early becomes transversely segmented to form a series o± mesoUastw somites or protoverteirw, which lose their cavities (Fig. 6, A and ±5} and are concerned in the formation of the vertebral column, body muscles, and urinogenital apparatus. As a general rule a thickened disc-shaped region can be recog- nised at a certain stage of development on the dorsal pole of the JM. ^UihnV -piQ, 7.—DiAGEAMMATIO TRANSVERSE SECTION THROUGH THE BoDY OF AX AdULT Vertebrate. Med, spinal cord ; JVB, neural tube ; KIV, body-wall; Co, dermis ; Ep, endodermic epithelium of alin\entary canal (intestine) ; VR, visceral tube ; Ao, aorta ; Ms, mesentery ; Per, parietal layer of the peritoneum ; Per^, visceral layer of the peritoneum ; il/sc, muscular coat of intestine ; iSubm, connective-tissue coat of intestine ; DIf, lumen of intestine ; W, vertebral centrum with dorsal arch. oosperm : this is the so-called embryonic area, and on it the first indications of the body are seen. This region gradually becomes constricted off from the yolk by the formation of furrows at its anterior and posterior ends as well as laterally, and consequently the connection of the body-rudiment with the ventral yolk-sac (the 1 The coelome may arise as a segmentally arranged series of pouches (enteroccehs) from the archenteron, in which case its lining epithelium is at first continuous with the hypoblast, as is most plainly seen in Amphioxus ; or it may be formed secondarily by a splitting (delamination) of the mesoblastic tissue (schir-octde). The first of these must be considered as the iijore Please note that these images are extracted from sca
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanatomycomparative
