178 DR. F. A. JENTINK. MAMMALS. 



Director Marquis G. DoRIA, so that I am absolutely sure of the indentification. It hardly 

 can be supposed that spécimens of this species once hâve been brought over from New 

 Guinea to the Aru Islands, so that the living both on New Guinea and on the Aru Islands of 

 this species is another proof for their land-connection in times past. However, notwith- 

 standing there seems to be no question about the original locality — the Aru Islands — it 

 is a very remarkable fact, that nobody since 1875 saw another spécimen from the named 

 islands; the more strange as earlier than BECCARI our traveller, C. B. H. VON ROSENBERG, 

 collected spécimens, now in the Leyden Muséum, of Plialanger macnlatus as well as of Phalanger 

 orientalis on thèse islands, and WALLACE too procured from there spécimens belonging to 

 thèse two species, now in the British Muséum. 



This may be as it is, it remains however a fact that PETERS described this species in 

 such clear terms, that merely lack of material may be an excuse why later authors failed to 

 accept it as a species distinct from orientalis. Indeed, extremely striking is the kind of fur 

 and its colour as well as the naked tail, only adorned round its base with a rather small 

 ring of hairs; moreover the skull, concave like in orientalis, présents a dentition quite distinct 

 from the same organs of the latter species, especially by the very stout comblike posterior 

 premolar (p*) in the upper- as well as in the lower jaw, placed by far not so correctly in 

 the row as is the case in ail other Plialangei'-species. 



The skeleton of N°. 277 (çf) présents 13 thoracic, 5 lumbar, 3 sacral and 26 caudal 

 vertebrae ; the skeletons of Nos. 43g a nd 435, both 9. hâve 13 thoracic, 6 lumbar, 2 sacral 

 and 27 caudal vertebrae, so that thèse C-skeletons of gymnotis hâve 1 lumbar vertebra more 

 and 1 sacral vertebra less than the çf-skeleton. As 439 (9) is so very old that, although 

 the animal is smaller than 277 (çf ), some of the molars are about completely worn down, 

 the différence in the number of vertebrae therefore cannot find an explication in the âge of 

 the individuals; moreover the skeleton of the type-specimen in the Genoa-Museum is that of 

 a maie too, but lias the vertebrae-formula like our female-skeletons, so that the above 

 mentioned particularity neither can be explained by sex; we must conclude that it represents 

 an abnormality, or — must perhaps the Regen Island spécimen be separated specifically? We 

 are wanting more material. A remarkable, perhaps sexual différence between the çf-skeleton 

 and 9" s keletons is that in the old çf ( 2 77) the sternum has a much stronger and larger 

 presternum, has 4 segments in the mesosternum and a not broadly ending xiphisternum, 

 while the very old 9 an d young (439 and 435) hâve 5 segments in the mesosternum 

 and a broader ending xiphisternum. Of our orientalis-specimens the skeletons présent 13 

 thoracic, 6 lumbar, 2 or 3 sacral and ± 28 caudal vertebrae, the mesosternum 4 segments, 

 and the xiphisternum is shaped like in gymnotis, showing therefore no sexual différences. 

 Some measurements of the old çf (277): 



mm. mm. 



head and body 650 skull: basai length 93 



tail 340 greatest breadth 6j 



ear 31 nasals, length 37 



hindfoot 70 palatal length 59 



The nasalia are more prominent and the anterior part of the lower jaw is more arched 

 than in orientalis. 



