. Chordate morphology. Morphology (Animals); Chordata. otic process of quadrate cartilage superficial ophthalmic VII, ^ ascending process phenethmoid commissure hyomandibulo .occipital arch Meckel's cartilage' epiphyseal tectum hypophyseal fenestra lamina tronsversalis anterior orbitonasol lamina pituitary vein synotic tectum otic capsule basihyol. hypohyal Meckel's cartilage lateral head vein Figure 4-39. Development of chondrocrcnium of Neocerofoc/us. A, B, dorsal and lateral views of head skeleton of 1 2-mm larva (After DeBeer, 1937); C, ventral view of head skeleton of 1 larva (a
. Chordate morphology. Morphology (Animals); Chordata. otic process of quadrate cartilage superficial ophthalmic VII, ^ ascending process phenethmoid commissure hyomandibulo .occipital arch Meckel's cartilage' epiphyseal tectum hypophyseal fenestra lamina tronsversalis anterior orbitonasol lamina pituitary vein synotic tectum otic capsule basihyol. hypohyal Meckel's cartilage lateral head vein Figure 4-39. Development of chondrocrcnium of Neocerofoc/us. A, B, dorsal and lateral views of head skeleton of 1 2-mm larva (After DeBeer, 1937); C, ventral view of head skeleton of 1 larva (after Bertmar, 1959); D, lateral view of head skeleton of larva (after Bertmar); E, dorsal view of head skeleton of 20-mm larva with part of left side cut away (after DeBeer); F, lateral view of head skeleton of 27-mm larva (after Holmgren and Stensio, I 936); G, sectional view of head skeleton, looking forward, showing relationships of parts of hyoid arch to other structures (after Bertmar, 1959, and Goodrich, 1930) suprahyal lies between the palatine and hyomandibular branches of the facial nerve and its suprahyal process extends upward to contact and fuse with the otic capsule lateral to the head vein. Thus the lateral commissure is formed from the pharyngosuprahyal. Meanwhile an epihyal chondrification has appeared above the symplectic, and this center is joined above by a latero- hyal center of subepidermal mesenchyme. The latter element expands, chondrifies, and fuses with the epihyal to form the hyomandibula of the adult, which lies behind the hyoman- dibular branch of the facial nerve. The symplectic may fuse with the quadrate, lie in the ligament joining the quadrate and ceratohyal, or disappear. The hyomandibula is better developed in the crossopte- rygian, where it articulates with the lateral commissure by two heads, above and below the level of the head vein. This is the same situation as in the actinopterygian. Although the stapes of the tetrapod has been c
Size: 1802px × 1387px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionameri, bookcollectionbiodiversity
