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Show 1895.] HEDGEHOG PROM SOMALILAND. 417 number of septa in the spines of a species i3 subject to considerable variation-in E. sclateri the lowest number being 21 and tbe highest 26, but, among spines of 88 specimens of the genus, I have found the variation to be even greater than this. The fur of this species has the coarse texture of E. europceus, and distinctive of all the smootb-spined Hedgehogs, whereas in the ridged-spined forms the hair is soft and silky. In E. sclateri, as in all the existing species of the genus, with the exception of E. europceus and E. pictus, tbe third upper incisor has two roots. In the former it has always one, but in the latter the condition of the teeth varies, as in three out of four skulls the third upper incisor has only one root; but this is probably due to the union of two roots, or to incipient division, as the root in these teeth is marked by a longitudinal furrow on each side. In the fourth skull the tooth has two distinct roots. This species (E. sclateri) has a double-rooted canine, which is the general character of this tooth throughout the genus. In E. europceus, however, the canine has usually only one root; but there are exceptions, as in five out of fifteen individuals observed by me it has two roots, while in the widely different E. pictus one out of four specimens examined has the tooth with only one root. The instability of the rooting of this tooth is further evinced by a skull of E. europceus in which the canine has a single root on one, and two roots on the opposite side. In E. concolor, which is very closely allied to E. europceus, the canine has two roots, as in E. algirus. In E. sclateri the first upper premolar, as in E. algirus, E. frontalis, E. albiventris, E. cethiopicus, and E. macracanthus, has two roots ; whereas in E. europceus, E. concolor, E. pictus, and E. micropus it has usually one root. On the other hand, in the forms that can be grouped with E. auritus, such as E. megalotis and E. grayi, the first upper premolar may have either one or two roots. The second upper premolar of E. sclateri has three roots, which is the general character of this tooth throughout the genus, with the exception of those species in which it is very feebly developed and occasionally shed even before the other teeth become worn, and in which it has only a single root. These species are E. micropus, E. pictus, and also E. cethiopicus ; but in the last I have met with an example with a double-rooted second upper premolar. Among the species in which it generally has three roots exceptions also occur, as Dr. Scully has recorded an instance (E. megalotis) in which only two roots are present, and I have observed three similar cases in E. grayi, a species which with E. megalotis may. possibly, be ultimately regarded as only varieties or local races of E. auritus- an opinion which has already been expressed by Dobson. The following are the external characters of this species :- Snout short; ears broadly rounded, but not so high as the inter-aural spines. Feet well developed; pollex twice as large as the hallux. Two large pads below the wrist, placed side by side, the external pad the larger. The fifth toe twice as large as the hallux; PROC. ZOOL. SOC-1895, NO. XXVII. 27 |