OCR Text |
Show 152 ON THE SKULLS OF LEMURS AND MONKEYS. [Feb. 19, the Lemurs, as well as in the Monkeys, not a primitive condition, but an extreme specialization. The postorbital region, to which the figures of Plate XIII. refer, has been examined in about 1100 skulls of Monkeys (exclusive of the Anthropoids, except Hylobates) and 300 of Lemurs; so that the ten figures are only just sufficient to give a general idea of the gradual changes. For all the particulars the reader is referred to a separate publication. In the characters of this region the Lemurs do not stand apart as has been supposed (Virchow) ; they represent the most generalized condition, closely related to what obtains iu the majority of the platyrhine Monkeys. From the Lemurs to the higher Monkeys takes place a gradual restriction and throwing back of the parietal, brought about by the greater extension, first of the malar, and subsequently of the frontal, alis-henoid, and squamosal. Phases in this whole process of evolution are the differences between the Platyrhinae and Catarhinae (discussed by Cuvier, Joseph, Anutschin, W . A. Forbes), and the union of the squamosal with the frontal; the latter being the terminal stage. As regards Man, the fronto-squamosal union is not an atavism ; where it occurs it is-apart from pathological cases-a specialization, just as in Monkeys. What has rather the appearance of an atavism is the spheno-parietal union when it occurs in the Gorilla and the Chimpanzee. EXPLANATION OF T H E PLATES. PLATE XI. Lacrymal region of Lemurs and Monkeys. Z.=lacrymal; mx. = maxillary; ma. = malar ; pl. = planum; cr.a.mx.=crista anterior of the maxillary ; cr.p.l. = crista posterior (of the lacrymal). Fig. 1. Nesopithecus australis Maj. (Br. M. G-eol. Dep.). 2. Nesopithecus roberti Maj. (Br. M. Geol. Dep.). 3. Mycetes palliatus, young (Br. M. Z. D. No. 96.6.1.1). 4. Propithecus edwardsi, young (Br. M. No. 75.1.29.6). 5. Cercopithecus albogularis 3 (Br. M. No. 92.10.18.9). 6. Mycetes palliatus (Br. M. Salvin's Coll.). 7. Chrysothrix sciureus (Br. M. No. 45.8.5.8). 8. Bhinopithecus roxellance J (Br. M. No. 99.3.1.2). 9. Papio anubis (Br. M. No. 45.6.17.14). 10. Papio sp. inc. (Br. M. No. 0.1.3.2). PLATE XII. Lacrymal region of Monkeys. Fig. 1. Brachyteles arachnoides (Br. M. No. 43.10.12.2). 2. Midas geoffroyi £ (Br. M. No. 0.5.1.63). 3. Colobus caudatus 3 (Br. M. No. 0.2.1.1). 4. Ateles fusciceps (Br. M. No. 1514 a). 5. Midas rufiventer (Br. M. No. 54 a). 6. Ateles vellerosus $ (Br. M. No. 89.12.7.2). 7. Callithrix personata (Br. M. No. 45.4.2.11). 8. Bemnopithecus natunee, 3 type (Br. M. No. 94.9.28.1). 9. Miopithecus talapoin 3 (Br. M. No. 0.2.5.8). 10. Macacus rhesus (Br. M. No. 58.6.24.144). 11. Nasalis nasicus (Br. M. No. 13 e). 12. Macacus nemestrinus (Br. M. No. 28 c). |