OCR Text |
Show 1901.] SKULLS OF LEMURS AND MONKEYS. 137 P. geoffroyi. The extra-orbital fossa is encircled entirely by the maxilla. A small intercalar bone (x), in the same position as the one mentioned in P. geoffroyi, is on its way to become soldered to the frontal. A second specimen of P. calabarensis (Br. M . Z. D. N o . 46.11. 10.5) is slightly older than the preceding. There is scarcely any pars orbitalis worth speaking of, the os planum reaching almost the crista posterior. On the right side it is almost completely joined to the lacrymal by synostosis, the suture being preserved only in the medial moiety ; on the left side (text-fig. 32) a process of the maxillary-bounded in front by the lacrymal, behind by the os planum-forms more than half of the crista posterior (laterally); the medial extremity of this latter is formed by the frontal. So that the lacrymal contributes ouly in a slight measure to the formation of the crista posterior; it is, however, more developed on the right side. The pars facialis of the lacrymal and its fossa proceed diagonally in an antero-external direction, and are delimited by the maxillary, which in front and laterally forms a real crista anterior, the latter being flattened medially, as is the case also in the former specimen. Tarsius. The crista post. 1. is formed by the lacrymal. The pars orbi-tedis I. is much reduced in size; the pars facialis I., bearing the fossa, is for the greater part, in front, entirely encircled by the maxilla. A fronto-maxillary suture. The malar remains far behind on the orbital margin, its anterior end being above the anterior termination of m. 2. Tarsius spectrum (Br. M . Z. D. No. 90.7.25.1). Teeth moderately worn.-Inside the orbit the os planum closely approaches the crista post., so that there is scarcely any pars orbit, lacr. Laterally from the os planum occurs a fontanelle. Outside the orbit, the maxillary, besides encircling the fossa, advances into the latter on its lateral side. Tarsiusphilippinensis, 3 (Br. M . N o . 97.3.1.1). Young specimen with deciduous dentition in place (text-fig. 35).- Similar to the preceding species, but the lateral part of the pars orbitalis lacr. has a larger extension. Tarsius, therefore, on the whole closely resembles the other non-Malagasy Lemurs in the conformation of the lacrymal region. Galago. The lacrymal is more reduced in size than in any of the Malagasy Leinuridae. The anterior boundary of the fossa lacrymalis, situated on the cheek, is always provided by the maxilla, which forms the roof of the canalis 1., and may also protrude more or less into the fossa. The malar may or may not reach the lacrymal. There never occurs a lacryrao-nasal suture. |