. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 180 ANNALS OF THE SOUTH AFRICAN MUSEUM DMA. 1mm Fig. 7. Ventrolateral view of the superficial neck musculature. vestigial girdle is united by the serratus muscle to the second and the third ribs. In T. vermis the pectoral girdle is absent (Hofstetter & Gasc 1969). In T. auran- tiacus the pectoral girdle is al^o absent, and the ribs consequently lack sternal attachments. It is therefore not possible to define a specific cervical region within the vertebral column of T. aurantiacus. In limbless squ
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 180 ANNALS OF THE SOUTH AFRICAN MUSEUM DMA. 1mm Fig. 7. Ventrolateral view of the superficial neck musculature. vestigial girdle is united by the serratus muscle to the second and the third ribs. In T. vermis the pectoral girdle is absent (Hofstetter & Gasc 1969). In T. auran- tiacus the pectoral girdle is al^o absent, and the ribs consequently lack sternal attachments. It is therefore not possible to define a specific cervical region within the vertebral column of T. aurantiacus. In limbless squamates such as ophidians (completely lacking a pectoral girdle) and amphisbaenids (lacking sternal attachments of the ribs) Hofstetter & Gasc (1969) divide the vertebral column into precloacal, cloacal and caudal regions. In this paper the term 'cervical' does not define a region of the vertebral column but refers only to that area on the precloacal region of the vertebral column from which the musculature responsible for the movements of the head arise. Typhlosaunis aurantiacus has procoelous vertebrae as in all saurians except the Gekkonidae. The broad elliptical condyles are slightly dorsally orientated and are as wide as the centra of the vertebrae. The first pairs of ribs are carried by the third vertebra, as in Acontias meleagris. The ribs are holocephalous (unicipital) and each has two tuberculiform processes close to the costal head: one anteroventrally and one postero- dorsally for the attachment of the intercostal muscles. A similar condition exists in T. vermis (Hofstetter & Gasc 1969). As a result of the increased func- tional importance of the cervical musculature in a limbless burrower such as T. aurantiacus, the synapophysis of the axis and the following three vertebrae are laterally extended to enlarge the area of origin of the cervical musculature. The atlas consists of paired neural arches and a ventral intercentrum. A neural spine is absent and the tw
Size: 2633px × 949px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
