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A reinvestigation of the segmentation of the crayfish abdomen and thorax, based on a study of the deep flexor muscles and their relation to the skeleton and innervation. I. The skeleton and intersegmental membranes
Author(s) -
Rayner M. D.
Publication year - 1965
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1051160307
Subject(s) - crayfish , biology , anatomy , segmentation , skeleton (computer programming) , thorax (insect anatomy) , artificial intelligence , ecology , computer science
Recent physiological studies on the crayfish Procambarus clarki (Girard), Astacura, Decapoda, have suggested the existence of certain anomalies between the classical interpretation of the segmentation of the crayfish and the more recently established segmental innervation patterns. An extensive reinvestigation of the skeletal segmentation has been undertaken, based on the dissection of both fresh and fixed specimens of this and two other crayfish species, to decide to what extent misinterpretation of the skeletal structure might provide an explanation of these apparent anomalies. As a result of this attempt to provide a self‐ consistent analysis of the crayfish skeleton, it has been necessary to conclude that the epimeral plate is tergal rather than pleural in origin, that the basal segment of the thoracic legs contains a subcoxal element, that this subcoxa exists as a free leg segment in the last thoracic legs and that the abdominal pleural folds are in part homologous with the subcoxae of the thorax. On the other hand it has not been necessary to diverge from the classical account of the segmentation, except to recognize the existence of a seventh abdominal segment (segment XXI) posterior to the uropod segment.