254 



MERISTIC VARIATION. 



[part I. 



The above includes six skulls from Waigiu, the individual peculiarities of 

 which are given below : 



The great variability of these skulls from the island of AVaigiu is 

 very remarkable. The 4 Leyden specimens were described by Jen- 

 tink'. In one of these there was besides no left upper 2nd molar, 

 which was entirely absent without trace, leaving a diastema between 

 m 1 and m 3 . In connexion with the variations of the dentition of P. 

 maculatus in Waigiu the following singular circumstance should be 

 mentioned. In all other localities the male P. maculatus alone is 

 spotted with white, the female being without spots, but in Waigiu the 

 females are spotted like the males 2 . This curious fact was first noticed 

 by Jextink (I.e., p. 111). 



In the other species of Phalanger no case of special importance met with; but 

 since in P. tirsinus p [ is normally (4 skulls seen) two-rooted, it may be of interest 

 to note that such a two-rooted condition of p l was seen on both sides as a variation 

 in P. ornatus, B. M., 1317, b (2 other specimens having single-rooted p^). 



*378. Trichosurus vulpecula ( = Phalcmgista vulpina). The typical 

 form of this species is Australian, while the large variety, fuliginosa, 

 is peculiar to Tasmania. In the typical form no instance of absence of 

 p]_ seen in 17 specimens examined. All possessed this tooth on each 

 side, and though varying a good deal in size, it was in every case well- 

 formed and functional, never being in a condition which could be called 

 rudimentary. 



Of the Tasmanian variety fuliginosa, 18 specimens (8 in B. M., 10 

 in C. M.) were examined. 



In 6 p] was present on both sides. 

 1 right side only. 



1 left. 



2 p] was absent altogether. C. M., 14 k and /. 

 Nevertheless in every case in which this tooth is present it is a large 

 tooth of about the size of the canines. In one case i^ 1 is two-rooted on 

 each side, as (Thomas, Cat, Marsup., p. 186) in the Celebesian Phalan- 

 ger ursinus. C M., 14 a, Hobart Town, Tasmania. 



Of the "intermediate" teeth in lower jaw one only is usually present, being 



1 The small premolar was accidentally described in the paper referred to as 

 being between the canine and p 4 , instead of between the anterior premolar and p*. 

 Jentink, in lift. 



- Compare the converse case of Hepialus humuli (the Ghost Moth), of which, 

 in all other localities, the males are clear white and the females are light yellow- 

 brown with spots; but in the Shetland Islands the males are like the females, 

 though in varying degrees. See Jenner Weir, Entomologist, 1880, p. 251, PI. 





