A treatise on zoology . them (the interdorsals).Farther back, in the caudal region (except at its extremity), thereappear to be alternate centra with and without arches. Here occuranterior centra bearing a pair of vestigial cartilaginous interdorsalsand a pair of similar interventrals, l»y i)OSterior centra AM 101 DEI 329 bearing separate arches above and below (Fig. 311). At thejunction between the two regions may be found intermediate con-ditions, incompletely divided centra (Fig. 306, D). Ivich pair ofcentra belongs to one segment and coriesponds to one spinal therefore
A treatise on zoology . them (the interdorsals).Farther back, in the caudal region (except at its extremity), thereappear to be alternate centra with and without arches. Here occuranterior centra bearing a pair of vestigial cartilaginous interdorsalsand a pair of similar interventrals, l»y i)OSterior centra AM 101 DEI 329 bearing separate arches above and below (Fig. 311). At thejunction between the two regions may be found intermediate con-ditions, incompletely divided centra (Fig. 306, D). Ivich pair ofcentra belongs to one segment and coriesponds to one spinal therefore represent one normal centrum divided into a pre-and postcentrum (pleiuo- and hypocentrum) (Schmidt [388],Schauinsland [384], Hay [203]). The extinct Amioidei showgreat variety in the structure of the centrum. Eurijcormv^ haspre- and postcentra as in Amia; but in the anterior region eachsegment is composed of an upper crescentic piece and a ventralrather larger piece; the series of doisal crescents are wedged in A
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Keywords: ., bookcentury1900, bookdecade1900, bookpublishe, booksubjectzoology
