632 
ME. W. H. FLOWEE ON THE DEVELOPMENT AND 
On examining the mouth, no traces of teeth were visible through the gums. The 
appearances seen after dissecting the alveoli were as follows (Plate XXIX. fig. 1) : — 
In the upper jaw the capsule of the first incisor was very large, and contained an 
uncalcified pulp, showing distinctly the form of the crown of the future tooth ; behind 
this was a small capsule containing the rudiment of the second incisor. Further back 
were two capsules containing distinct pulps of two teeth of the molar series, but as yet 
showing no trace of calcification. In the lower jaw a large procumbent incisor, 
of an inch long and partially calcified, occupied the anterior portion of the ramus. 
Above and behind this were the uncalcified pulps of two molars ; as in the upper jaw, 
the second was considerably larger than the first. Although these pulps were very soft, 
they showed distinctly the form of the summit of the crown of the future tooth. No 
other tooth-germs could be detected. 
2. A more advanced specimen of the same genus, in which the eyes were open, and 
the lips separated backwards to their normal extent, measured from muzzle to end of 
tail 11 inches, of which the head occupied 2’6 inches, and the tail 5 inches. No teeth 
had protruded through the gum, but the region of the upper incisors presented a bul- 
bous prominence ; the apices of the lower incisors were almost visible through the thin 
covering membrane, and prominences on the alveolar borders indicated the situation in 
which molar teeth were shortly about to break through their superficial investments. 
On dissection (Plate XXIX. fig. 2), in the upper jaw, the crowns of the first two inci- 
sors were found to be advanced in calcification, the first more forward than the second. 
Both presented the characteristic form and also size of the extremity of these teeth in an 
adult animal. The pulp of the third incisor occupied a capsule placed in the premaxillary 
bone at some distance from the alveolar margin. It represented only the extreme sum- 
mit of the tooth, and was not calcified. Behind the premaxillary suture was a minute 
conical calcified canine. Behind this the calcified germs of the teeth of the molar series. 
These were three in number, the first having the form peculiar to the premolars of the 
genus, compressed, and narrower in front than behind; the second (coloured red in 
the figure), which was the furthest advanced both in position in the alveolus and in 
development, had the quadrate form and characteristic anterior and posterior transverse 
ridges of a true molar. The third was also a true molar, but only the tips of the cusps 
were calcified. Immediately above the anterior part of the second was lodged a small 
rounded capsule (coloured blue in the figure), of a yellowish colour, perfectly distinct, 
though not more than inch in diameter. 
In the mandible, the large procumbent incisor, corresponding in form and size to the 
crown of that of the adult animal, was calcified to the length of yj inch. The molar 
series consisted of three calcified crowns, corresponding in general characters to those 
of the maxilla, i. e. having the form respectively of a premolar and two true molars, but 
they were rather more advanced in their growth. The capsule of a fourth was also visi- 
ble ; and underneath the fore part of the second tooth and to the outer side of the base 
of the incisor, was a small capsular germ similar to that observed in the upper jaw. 
3. In the next stage of dentition, the crowns of the first and second upper incisors 
