THE TEETH OF THE WOMBAT AND THE BEAVER. 



It is everyday knowledge to naturalists that, among the 

 marsupials of Australia, we have types which correspond 

 wth the various higher orders of old-world mammals, and 

 present features analogous to theirs, owing to their getting 

 their living in the same of several ways. For instance, the 

 Tasmanian wolf is carnivorous, the kangaroos are herbi- 

 vorous, and the wombat gnaws like a rodent. The matter 

 which concerns us here is connected with the teeth of the 

 last-mentioned animal. In Figures 32 to 34 the lower jaw 

 of a wombat is compared with that of a true rodent, the 

 beaver. The lower incisor of the latter is exceptionally 

 large, but the corresponding tooth in the wombat is also 

 very well developed (see Figure 34). It will be seen that it 

 is necessary to find room for the large incisors in both cases. 

 In the beaver, as shown in Figures 32 and 33, the molar 

 teeth, which are the only ones developed in addition to the 



incisors, stand high out of the jaw, and their sockets are 

 above that of the great incisor. In the wombat, in the 

 anterior part of the jaw at any rate, there is just the same 

 need for accommodating the incisor socket; but it wll 

 be seen that the surfaces of the molar teeth in this animal 

 project but little above the jaw, and it is by the curving 

 of the molar teeth that the difficulty has been got over, 

 the sockets ending below the level of the incisor, and in the 

 case of the first grinding tooth coming directly underneath 

 it. The interest lies in the fact that the same necessity has 

 been met in two very different ways in a rodent and in 

 a marsupial. The specimens from which Figures 32 and 

 34 were taken are exhibited at the Eton College Museum, 

 to which Sir Edmund Loder kindly presented the beaver 

 jaw. 



W. M. W. 



THE FACE OF THE SKY FOR MARCH. 



By A. C. D. CROMMELIN, B.A., D.Sc, F.R.A.S. 



Table 10. 



T.\BLE 11. 



P is the position angle of the North end of the body's axis 

 measured eastward from the North Point of the disc. B, L 

 are the heUo-(planeto-)graphical latitude and longitude of the 



centre of the disc. 

 For the future the data for the Moon and Planets in the 

 Second Table will be given for Greenwich Midnight, i.e., the 



Midnight at the end of the given day. 



The letters m, e stand for morning, evening. The day is 



taken as beginning at midnight. 



The Sun is moving Northwards at its maximum rate, 

 crossing the Equator 21'' 4'^ SI"" e. Its semi - diameter 

 diminishes from 16' 10" to 15' 2". Sunrise changes from 

 6" 50" to 5" 42" ; sunset from 5" 36" to 6" 28"°. 



Penumbral Eclipse of Moon. — There vi-ill be a 

 Penumbral Eclipse of the Moon on March 1st about 7*" e. 



A slight smokiness will be discernible on the Northern 

 portion of the disc. 



Mercury is a morning star in W. elongation, 27° 43 

 W. of Sun on 20th. Semi-diameter diminishes from 5" to 3". 

 Illumination increases from I to 5. 



Venus is a morning star. Illumination increases from 

 3 to iV- Semi-diameter diminishes from 10" to 8". 



The Moon.— Full l" 6" 33" e. Last quarter 8'' O" 28" e. 

 New 15* 7" 42" e. First quarter 23^ lO" 48" e. Full 

 31* 5" 38° m. Perigee 5" 3'" m. Apogee ai* l"- m, 

 semi - diameter 16' 19", 14' 46" respectively. Maximum 

 hbrations 7* 7" N., 12* 5° W., 20* 7° S., 27* 7° E. The 

 letters indicate the region of the Moon's limb brought 

 into view by libration. E., W. are with reference to our 

 sky, not as they would appear to an observer on the Moon 

 (see Table 12). 



Mars is invisible, having been in conjunction with the Sun 

 on Dec. 24tb. 



Jupiter was in conjunction with the Sun on Feb. 24th, 

 and is therefore practically invisible this month. 



Saturn is between Taurus and Gemini. In perihelion 

 Feb. 21st. Stationary Feb. 26th. In quadrature Mar. 17th. 

 Polar semi-diameter 9". Major axis of ring 42", minor 19". 

 Angle P-5°-7. 



47 



