450 Mr. J. L. Bonhote on 



two am in no position to give a definite opinion ; they are 

 merely included to show in what relationship tlicy stand to 

 the group as a whole, and in order that any future worker 

 may bear them in mind when studying this group. On this 

 last race, however, I feel compelled to make a few remarks. 

 ]\Ir. ]Miller starts his description by giving as its distinctive 

 characters, " Skull with more slender rostrum and smaller, less 

 inflated audital bullae," both characters being comparative. 

 In the study of comparative characters one naturally looks at 

 the dimensions, in order to get some idea of the amount of 

 the difference between the two f^rms ; and in this case we are 

 met with the announcement that " The skull is so nearly 

 alike that of S. anamhensis in size, that it is unnecessary to 

 give detailed cranial measurements." In other words, were 

 it not for a description of the audital bullae we should have a 

 species characterized by comparative features of size alone, 

 which are incapable of being demonstrated on paper by 

 measurements. It will, perhaps, make my meaning clearer 

 if I quote Mr. Miller's description in full: — "Skull much 

 like that of S. anamhensis in size and general form. The 

 rostrum is more slender, particularly when viewed from 

 below, and the audital buUse are noticeably different in 

 form. The buUee are so flattened that when viewed from 

 behind (the skull held upside down) they appear to rise 

 scarcely above the level of tips of hamulars. Each is con- 

 stricted near the middle by a groove extending from just 

 behind the lateral process of basioccipital over the ventral 

 ridge of the bulla and disappearing on the outer side. This 

 groove, faintly indicated in the related species, is here so 

 orcatly developed as strongly to affect the shape of the bulla}, 

 particularly when viewed from the side." 



The dii^tinction of the groove on the bulla, although more 

 pronounced in Mr. Miller's specimens, is, judging from the 

 analogy of the skulls of other races of S. vittatus, a very 

 variable feature, two skulls from the same locality in Borneo 

 showing varying degrees of constriction. The only charac- 

 teristic of this species left, therefore, is that the bullae are so 

 flattened that " when viewed from behind (the skull held 

 upside down) they appear to rise scarcely above the level of 

 tips of hamulars.''^ 



1 should be the last to maintain that such small differences 

 where they exist should be disregarded, and, in fact, the less 

 obvious they are the more interesting are tiiey likely to prove 

 in future ages, as showing what may be the first incipient 

 beginnings of a definite species ; but when these differences 

 are so minute as to be incapable of being definitely expressed, 



