50—16 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
existing Asiatic species of the genus. Rolleston^ regards S. cristakis, S. vitlatus, and 
S. leucomystax as forming a closely allied group, and thinks it highly probable that 
the two last may be all but identical ; he also considers S. andamancnsis, 8. j)apuensis^ 
and 8. timoremis as another group intimately related to the first. Prof. Rlitimeyer'^ 
unites 8. leucomystax and 8. vittatus^ and regards the 8. anclamanensis group as smaller 
races of the same. Prof. Forsyth-Major® thinks that (excluding Potamoclmrus and 
P or cilia (S. salvanius)) there are but four existing species, vis., 8. scrofa, 8. harhatus^ 
8. verrucosus, and 8. vittatus ; the latter including 5'. cristatus, .8 leucomystax , the 8. 
andamanensis group, and some other forms. All are agreed in regarding 8. celehensis 
as intimately related to, or identical with, 8. verrucosus. 
8. barhatus is readily distinguished by its elongated cranium, and the extremely 
short 111 . 3. 8. scrofa, according to Rolleston, is distinguished from 8. verrucosus and 
the 8. vittatus and 8. andamanensis groujis, by the form of the lachrymal, and the 
relatively long facial portion of the cranium. In males of 8. cristatus the talon of 
ill. 3 is more complex than in 8. scrofa, and in most instances the length of m. 3 
exceeds that of ni. 1 , m. 2 , and in all examples that the writer has seen the length of 
m. 3 exceeds that of m. 1 and m. 2 .‘^ In 8. vittatus in. 3 is normally shorter than in N 
cristatus ; its length, especially in the lower jaw, in all typical examples® that have 
come under the writer’s notice being less than that of m. 1, in. 2. There may be 
exceptions, but these points are generally characteristic of the two forms. In 8. 
andamanensis^ in. 3 has a still smaller talon, and its length is still less in proportion to 
that of m. 1, m. 2. On these grounds the present writer is inclined to continue to 
apply separate names to the Indian 8. cristatus, the Javan (etc.) 8. vittatus, and the 
smaller 8. andamanensis, even if certain forms indicate a more or less complete 
transition between them.’’ In 8. verrucosus the length of m. 3 is usually about the 
same as that of m. 1, m. 2. 8. salvanius is distinguished from all by its diminutive 
size. The river-hogs comprise 8. afrieanus of S., and 8. porcus of W. Africa : the 
skulls of these species are readily distinguished by the great development of the 
protuberance above the canine. 
Fossil There is great difficulty in deciding on the number of European 
fossil species ; and the following list® Avhich comprehends the best-defined forms must, 
therefore, be regarded as purely provisional. The confusion in the synonomy is, 
indeed, so great, that the only way to arrive at a thoroughly satisfactory conclusion 
1 ‘ Trans. Linn. Soc.’ Zool., ser. 2, vol. I., pp. 251-286 (1877). 2 ‘ Verh. nat. Ges. Basel,’ vol. VI., pt. 3 (1877). 
3 Cams’ ‘ Zoologischer Anzeiger,’ vol. VI., pp. 295-300 (1883). 
4 In one specimen in tte Brit. Mus. (No 1716 S.) m.3 is abnormally short, its length being less than that of m- < . m . 2 ; 
mTs is, however, longer than lilTi, mTa. The same seems to be the case with the male skull figured by Bolleston. These 
specimens are, therefore, exceptions to the general rule given on page 56. , 
6 No. 1362 B., British Museum., is an exception, but this specimen not improbably belongs to S. verrucosus. 
6 Eolleston, op. cit., p. 262, pi. XLIII., fig 8. 
7 The writer would not be deterred from applying distinct names to two well-marked forms which are more or less 
connected by other forms, for it is evident that if such connections bo wanting this is merely due to their extinction. 
8 It should be observed that here, as elsewhere, the references do not always refer to the original descriptions of the 
different species, but merely to memoirs where good figures or descriptions may be found. 
