4 ON THE SKULL OF TARSIPES ROSTRATUS. 
The dental formula of Tarsipes has been stated differently by different 
observers, and apparently varies in different individuals. In this specimen the 
formula appears to be— 
one 1 2 
noe = » (Y= = 
pO gp O& Cap Ms 
being less by an upper and lower molar than that usually received. The lower 
incisors are long, lanceolate, and in a straight line with the fuble mandibular 
ramus; the other teeth are all small, and the canines and molars have blunt 
rounded crowns.* 
The whole skull is 21°5 mm. long, and 9 mm. in its greatest breadth. The 
greatest height of the mandible is ‘8 mm., its average height is “6 mm.; the con- 
dyle is 1 mm. long by “6 mm. wide; the whole mandibular ramus is 13°8 mm. long, 
beyond which the incisor tooth projects 2°6 mm. 
In my paper on the Development of the Skull in the Insectivora (Phil. Trans., 
1885), I have discussed at length the general characters of the Marsupial skull, and 
it is interesting to note how fully these characters are maintained in the skull of 
Tarsipes, reduced and to some extent degenerate as it is. Thus we see in Tarsipes 
(1) the small size of the frontals compared with the nasals and parietals, and the 
relatively enormous development of the squamosals; (2) the large lachrymals with 
their greatly developed facial plates; (3) the imperfect, as it were schizognathous 
palate, with accessory interpalatine bones ; (4) the small pterygoids and vomer ; (5) 
the long jugal, coming into relation with the lachrymal in front, and with the glenoid 
cavity behind; (6) the small nasal labyrinth, and the small squarish cribriform 
plate ; (7) the small orbitosphenoids, flush with the alisphenoids, and with a notch 
instead of a complete foramen for the optic nerve; (8) the relation of the ali- 
sphenoids to the drum-cavity; (9) the perforation of the basisphenoid by the 
carotids, and the imperfect development of the pituitary fossa and clinoid pro- 
cesses ; (10) the small perforation in the stapes. Almost the only aberrant points 
to be noted in Tarsipes are the partial anchylosis of the tympanic, the absence of 
the inflected angle in the mandible, and the circumstance that the lachrymal 
excludes the maxillary from articulation with the frontal. The brain-cavity is 
comparatively large, but this is usually the case in the smaller members of any group. 
But, on the other hand, the special characters of the skull in Tarsipes give us little 
if any help in seeking its relations among neighbouring genera. In the general 
form of the skull, the absence of any postorbital processes, the shape of the 
mandible as well as in the characters of the dentition, Tarsipes differs from all the 
other Phalangistidee. 
* That the animal is at least partly insectivorous appears to be proved (vide Gounp, Austr. Mamm., 
pt. 1, and Tuomas, Brit. Mus. Cat. of Marsup., 1888, p. 134 ); but the stomach of our specimen was quite 
full of honey and pollen. The large lower incisors are evidently functional, and perhaps find their 
use in piercing or tearing asunder the parts of the flower. 
