PURBECK FORMATIONS. 49 



itself, show it to be part of a bony palate, broken and bent up into its present position by 

 posthumous pressure. The part {b), moreover, continued from the sockets of the three 

 last molars, retains an inward curve or bend therefrom, suitable to its palatal character, 

 and not in accordance with the disposition of either the inner or outer plate of the ramus 

 of any mandible in the present series of small mammalian fossils. 



With this determination the general curve of the molar series also accords : it inclines 

 outward from the canine, and, after a straight course, bends inward at the end of the 

 series, the hinder half of which is thus convex outwards or horizontally. Vertically the 

 series presents, as in the upper molars of Marsupials and Insectivores, a slight sigmoid 

 disposition. 



Assuming then that we have — or rather are detecting — in the present specimen, the 

 dentigerous part of the left upper jaw, it exposes the inner side of the teeth, and also the 

 working surface of the last three molars (;« 5, 6, 7). The teeth, in sitii, are the canine (<?), 

 and eleven of the premolar-molar series. 



Of the incisors nothing can be said, satisfactorily or confidently, beyond the fact that 

 there are, in the portion of crushed bone, d, anterior to the canine, feeble indications of their 

 alveoli. 



The canine (c) is a formidable tooth; its crown is more than twice the length of that of 

 the longest molar; it is gently bent, as it descends, backward and a Uttle inward, is 

 strongly indented at the middle of the inner side of the base, the indent widening to the 

 socket, as if indicative of a division, or disposition to divide, into two roots. A like indi- 

 cation was noted in the lower canine of Siylodon pusillus. 



Close behind the canine projects the crown of a minute premolar (jo 1), of a simple, 

 subcylindrical, obtusely pointed form. After an interval there is an indication of a similar 

 minute premolar {p 2). Then follows a premolar [p 3), having for its crown a broader 

 based conical cusp with a minute tubercle before and behind : this tooth is not longer than 

 the first, but is much broader from before backward ; it is implanted by two roots. Imme- 

 diately follows a much larger and longer premolar [p 4), the conical crown of which does 

 not show the basal tubercles. The next tooth {m 1) presents the form of the exposed inner 

 surface common to the rest of the molars ; viz., that of a cylindrical column truncate atop: 

 this terminates internally a crown which expands slightly as it extends outward ; the inner 

 cusp does not reach the level of the apex of the antecedent premolar, and the sudden 

 loss of size in m 1 significantly recalls that character in the type mandible (PI. II 

 fig. 15). The second molar {m 2) in the upper jaw (fig. 14) is merely augmented in size : 

 it shows more of the dark-coloured cement-covered base before the bright amber-coloured 

 enamel begins. The following molar {m 3) is similar. The fourth of these molars {ni 4) 

 shows a shght outswelhng of the enamelled base of the crown and the summit of the inner 

 column is less worn, rising to an obtuse point. The fifth, sixth, and seventh molars 

 (m 5, 6, 7) decrease progressively in length ; they slightly expand to the outer side, which is 

 divided by a mid-longitudinal cleft (fig. 14, b, c c) into two low cusps. The grinding 



7 



