NYCTALUS 



57 



The skull is massive and flat ; the brain-case angular ; the 

 nasal region somewhat inflated ; the premaxillary gap large, 

 somewhat pointed above, deeply rounded below ; the zygomata 

 are moderately flattened ; the cranial crests not prominent ; the 

 auditory bullae moderately large (Fig. 4, No. i, p. 56). 



There are thirty-four teeth (Fig. 5), arranged as — 



3-3 



I - I 



pm 



2-2 



3-3* 



The upper incisors are arranged in pairs, inclined inwards, and 

 separated by the wide interval of the premaxillary gap in 



Fig. 5. — Diagram of Arrangement of Teeth in Genus Nyctalus. 

 (l) Upper, and (2) Lower Jaw. 



their midst : the outer of each pair lie close and parallel to, 

 but are shorter than the inner. The anterior upper premolar 

 is minute, and lying in the internal angle between the canine 

 and the posterior premolar, which meet externally, is invisible 

 from without. 



According to the best authorities, this genus represents 

 the most specialised form of the Chiroptera, amongst which it 

 is nowhere excelled in power of flight ; a remarkable change of 

 opinion, since in 1878 the leading authority of the day — 

 Dobson {Catalogue of Chiroptera, 100) — wrote that "From 

 whatever point of their structure they may be considered, the 

 Rhinolophidse are evidently the most highly organised of 

 insectivorous Bats." 



