. Journal of comparative neurology . excep-tion that they appear before the epibranchial placodes. The preauditory placodeis absent and the lateral line primordium is larger than in figure 2. In the post-auditory region the second ectodermal gill thickening is split at its anterior endinto two portions of which the more dorsal represents the posterior extension ofthe second gill and the more ventral the area of contact of the third gill. Theposterior portion of this second thickening is the angular thickening. 4 Reconstruction of Stage XIX; age 106 hours; length mm.; shading andabbreviatio
. Journal of comparative neurology . excep-tion that they appear before the epibranchial placodes. The preauditory placodeis absent and the lateral line primordium is larger than in figure 2. In the post-auditory region the second ectodermal gill thickening is split at its anterior endinto two portions of which the more dorsal represents the posterior extension ofthe second gill and the more ventral the area of contact of the third gill. Theposterior portion of this second thickening is the angular thickening. 4 Reconstruction of Stage XIX; age 106 hours; length mm.; shading andabbreviations as in figure 1. This stage shows the first trace of the primordiumof the mandibular lateral line, also the first trace of the postauditory lateralline. There are present three gill thickenings posterior to the ear associated withthe first, second and third gills. The posterior extension of the third thickeningrepresents the angular thickening. 620 LATERAL LINE PRIMORDM IN LEPIDOSTEUS OSSEUS p. L. LANDACRE AND A. C. CONGEB PLATE 2.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmedicine, bookyear191
