. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. 20 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. the ear capsule substantially as in Stage II., there being just room for the eye — now, of course, increased in size — to pass between the front end of it and the ethmoid. The right supraorbital becomes a little more arched as the fish increases in depth. The wings of the ethmoid extend out from the mid-line farther proportionally and are more flat- tened antero-posteriorly. Upon the surface of these wings of the eth- moid cartilage the ect-ethmoid bones, or pre-fro
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. 20 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. the ear capsule substantially as in Stage II., there being just room for the eye — now, of course, increased in size — to pass between the front end of it and the ethmoid. The right supraorbital becomes a little more arched as the fish increases in depth. The wings of the ethmoid extend out from the mid-line farther proportionally and are more flat- tened antero-posteriorly. Upon the surface of these wings of the eth- moid cartilage the ect-ethmoid bones, or pre-frontals, are later formed. i?b. su''orb. dr.^r- pt-pal. s.\. pt-pal. dx. crt. ink. dx. trb. su^orb. s. p. , i^ris. eth. ms-eth. ec^eth. s. ^for. olj s. ':rt. orb. a. pi-pal. s. Fig. B. * Oblique view of the facial cartilages of P. americanus, Stage III. Photographed from a model, as in the case of Fig. A. X circa 75. For meanmg of lettering, see Abbreviations under Explanation of Plates. The gape has been greatly increased by the growth in length of all the facial cartilages, but these have not increased in diameter propor- tionately. The pterygo-palatine bars, which from the first support the upper jaw, in lengthening have come to lie nearly parallel to Meckel's cartilage, and their articulation with the quadrates is so far posterior that the one of the left side alone falls within the region modelled. At this stage these cartilages are in some instances so reduced in diameter toward their posterior ends, as to show in cross sections only one cartilage cell. A process from the left wing of the ethmoid has fused with the. 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 Harvard University. Museum of Comparative Zoology. Cambridge, Mass. : The Museum
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Keywords: ., bookauthorha, bookcentury1800, bookdecade1860, booksubjectzoology
