. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. From the anterior border of the foramen the sides of the preparietal diverge in anterior direction. The preparietal thus meets the frontal in a long transverse suture. The whole of the bone lies in a depression. Direct comparison proved the identity of this specimen with a form from the Luangwa Valley of Northern Rhodesia which I described under the name Dicynodon roberti. This specimen now bears the South African Museum Cat. No. 11706. (b) In another frag- ment (fig. 1) the pineal foramen pierces a
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. From the anterior border of the foramen the sides of the preparietal diverge in anterior direction. The preparietal thus meets the frontal in a long transverse suture. The whole of the bone lies in a depression. Direct comparison proved the identity of this specimen with a form from the Luangwa Valley of Northern Rhodesia which I described under the name Dicynodon roberti. This specimen now bears the South African Museum Cat. No. 11706. (b) In another frag- ment (fig. 1) the pineal foramen pierces a large oval boss which is almost entirely formed by the preparietal. The pos- terior third of the boss is formed by the parietal, but this bone only stretches two-thirds up the posterior surface of the boss and is thus excluded from the border of the pineal foramen. The preparietal completely surrounds the foramen, which is of medium size and nearly circular. The foramen is directed anteriorly, and the plane in which it lies makes an angle of 45° with the plane of the dorsal sur- face of the skull. Pos- teriorly, the surface of the boss, here formed mainly by the parietal, slopes gently backwards. The parietal, which has only a small exposure, is then covered by the two post-orbitals which meet on the median line. Anteriorly, the boss is abruptly marked off from the surface of the frontals by a semi- circular groove. A near approach to this condition of the pineal region, in the more fully known Karoo species, is shown by some of the species of the genus Platycyclops, where the foramen is also completely surrounded by the preparietal raised in the form of a boss. A nearer approach still is shown in the species of the genus Megacyclops, where the parietal participates in and forms the posterior part of the boss. In the present specimen the shape of the boss diners remarkably. Fig. 1.—Neomegacyclops cyclops n. sp. Cat. No. 11707. a, dorsal view of pineal region (X^). b,
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
