574 PHILOSOPHICAL TRANSACTIONS. [aNNO J 7 10. 



with the hind tooth. Not only both the hind teeth are free from grinding, but 

 also part of the fore teeth of the left side. These teeth, as Dr. Moulins well 

 observes, are all molares, being 1 inches broad; that part of them which grinds 

 is 6-1- inches on the right side, and 5-|- on the left. Their surface, though flat, 

 yet is very unequal ; for they have alternately placed (running from the right 

 to the left) a hollowness, and then an eminence, and this eminence is sur- 

 rounded by a rough protuberant border. There are nine of each of the holJow- 

 nesses, and as many eminences, undulated, as they use to paint sea waves. 



It is well known, that immediately below the coronas there is a pretty large 

 hole, in proportion to the animal, for the emission of a branch of the external 

 carotid artery, jugular vein, and 5th pair of nerves, called maxillaris inferior, 

 which are dispersed in the roots of the teeth for their nourishment, and for 

 conciliating to them that quick sensation of pain, which those affected with the 

 tooth-ach are very sensible of; and that in this hole in sheep, calves, and other 

 quadrupeds, especially such as are young, as also in children before the 7th 

 year, and even afterwards for some time, in the cavous part of the bone, where 

 the teeth do not penetrate the jaw, there are rudiments of teeth to be seen 

 cavous in that extremity, which is towards the base, (in which the ligaments 

 that keep the root fixed are firmly impacted) and solid at the other extremity; 

 so in this animal from the fore- mentioned large hole, I observed several of these 

 rudiments of teeth lying stratum super stratum, or rather placed perpendicu- 

 larly across the bone of each other side, from the hole, till the teeth began 

 to appear. Those that were placed nearest the hole were smaller, not above 

 1 inch in breadth, and -f inch in length, i. e. from above to below, cavous at 

 the lower or back part, (for reception of the ligament, which is guarded by two 

 thin hard laminae) and solid at the other. Those nearest the hole were two or 

 three times intersected by membranes, by which they could be disjoined. But 

 after I had taken out several, I found no more such a separation, but that from 

 the right to the left, they were wholly cavous : each of them was invested by 

 a membranous tunicle, as it were a periosteum, and had something like a carti- 

 laginous substance between the two. Their surface is very unequal at the orifice, 

 where they receive the ligaments and vessels, and as if they had been folded 

 into several plicae, and afterward taken asunder, from which there ran several 

 ridges and sulci, from one extremity to the other ; where the ligaments cease, 

 they become extremely solid and ponderous, and at their upper extremities half 

 round, and sometimes formed into digitations. When they approach to that 

 part of the bone at which the teeth appear, they begin to quit the periosteum, 

 by which they were distinguished, and unite close together, so as to form one 

 bone. It is observable, that at their upper extremity there is a lamina, which 

 being convex toward the jaw, and concave toward these rudiments of teeth, do 



