. The elements of Embryology,. IX.] THE MAXILLAKT PROCESS. 229 appears when taken by itself somewhat remarkable, and led to the view, formerly very general and still held by many, that the superior maxillary process was equivalent to a visceral arch. Mr Parker has recently shewn that in both Osseous fishes and the Elasmobranchii all the anterior arches undergo a somewhat similar segmentation, and it appears therefore to be a fair deduction that this sesfmentation • • t • • • persists m the chick in the mandibular arch, while it has been lost in the others. None of Mr Parker's investigations on
. The elements of Embryology,. IX.] THE MAXILLAKT PROCESS. 229 appears when taken by itself somewhat remarkable, and led to the view, formerly very general and still held by many, that the superior maxillary process was equivalent to a visceral arch. Mr Parker has recently shewn that in both Osseous fishes and the Elasmobranchii all the anterior arches undergo a somewhat similar segmentation, and it appears therefore to be a fair deduction that this sesfmentation • • t • • • persists m the chick in the mandibular arch, while it has been lost in the others. None of Mr Parker's investigations on the lower vertebrates support the view that the maxillary process is an aborted anterior arch. Similar views as to the nature of the maxillary process have been arrived at by Gegenbaur (loc. cit), from his investigations upon the crania of the cartilaginous Fishes. 7. The cartilage or differentiated mesoblast appears in the maxillary process later than in the mandibular arch. Fig. View fbom below of the Paired Appendages op the Skdli, op a Fowl ON THE FoUETH Dat OP INCUBATION. (From Parker.) e» I cerebral vesicles. 6 eye. /wfronto-nasalprocess, w nasal pit. ir trabeculse. pts pituitary space, mr superior maxillary process, pg pterygoid, pa pala- tine, q quadrate, mk Meckel's cartilage, ch cerato-hyal. hh basi-liyal. chr ceratobranchial. ebr proximal portion of the cartilage in the third visceral arch. Ibr. basibranchial. i first visceral cleft. 2 second visceral cleft. 3 third visceral 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 Foster, Michael. London : Macmillan
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Keywords: ., bookcentury1800, bookdecade1870, bookpublisherlondo, bookyear1874
