![. Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior ... . Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior ...](https://c8.alamy.com/zooms/9/f574404171724b1fa7bb92992bee6c2a/reffxf.jpg)
. Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior ...
![. Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior ... . Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior ...](https://c8.alamy.com/zooms/9/bda495223dc546c689162402abd28706/reethy.jpg)
. Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior ...
![. Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior ... . Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior ...](https://c8.alamy.com/zooms/9/eddb3c5a5e77471e94d98c23f544c1df/refg48.jpg)
. Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior ...
![Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior](https://c8.alamy.com/zooms/9/2f4fd67ddbe44f1c840b74d43e0567fa/reetkg.jpg)
Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior
![Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior](https://l450v.alamy.com/450v/reetjn/comparative-anatomy-anatomy-comparative-reproduction-91-if-quotanusquot-is-to-be-defined-as-the-posterior-aperture-of-the-digestive-tubedigestive-in-strict-sensethen-the-term-should-not-be-applied-to-the-external-opening-of-the-cloaca-but-rather-to-the-internal-aperture-between-rectum-and-cloaca-by-this-definition-the-proctodeal-aperture-would-ordinarily-become-the-external-cloacal-opening-but-in-some-cases-would-become-an-external-anus-teleostei-or-an-internal-anus-frog-if-the-posterior-extremity-of-the-adult-mammalian-digestive-tube-includes-a-remnant-of-the-embryonic-cloaca-reetjn.jpg)
Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior
![. Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior ... . Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior ...](https://c8.alamy.com/zooms/9/aa63510c3a28475ba1b19826e8039c4c/reet9w.jpg)
. Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior ...
![Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior](https://c8.alamy.com/comp/REETPD/comparative-anatomy-anatomy-comparative-reproduction-77-and-forward-from-the-primitive-streak-and-always-in-the-space-between-ectoderm-and-endoderm-this-layer-like-the-early-mesoderm-of-amphib-ians-is-unsegmented-and-devoid-of-cavity-in-the-sauropsidan-embryo-then-as-in-the-amphibian-rapid-growth-and-cell-proliferation-within-the-blastoporal-rim-is-the-primary-source-of-mesoderm-early-development-in-placental-mammals-the-early-development-of-placental-mammals-exhibits-features-peculiar-to-the-group-and-more-or-less-difficult-of-comparison-with-anything-in-the-development-of-lower-REETPD.jpg)
Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior
![Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior](https://c8.alamy.com/comp/REETN7/comparative-anatomy-anatomy-comparative-reproduction-8l-as-an-introduction-to-the-account-of-the-development-of-organs-in-vertebrates-reference-to-amphioxus-will-be-helpful-amphioxus-partly-because-it-is-so-small-and-partly-because-it-is-in-so-many-respects-primitive-affords-what-may-be-regarded-as-a-simplified-and-diagrammatic-view-of-the-early-relations-of-organs-organogenesis-in-amphioxus-in-the-preceding-account-of-the-early-development-of-amphioxus-the-embryo-has-been-followed-to-a-stage-where-the-mid-dorsal-ectoderm-has-become-delimited-from-the-lateral-ectoderm-to-form-the-neur-REETN7.jpg)
Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior
![Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior Comparative anatomy. Anatomy, Comparative. REPRODUCTION 93 region, carrying with them the coelom, and meet mid-ventrally to form a double vertical layer, a ventral mesentery, extending from the enteron prosencephalon proamnion anterior](https://c8.alamy.com/zooms/9/fce3b3c2bc1646bea0c5a557386ff409/refd17.jpg)