Xliv PLASTIC CHARACTERS. 



reversion to a colour pattern of the head of some common 

 ancestral form). 



Cynopterus section. — Brownish tinges with paler underparts are 

 the rule, except in Nyclimene. Myonycteris is practically llousettine 

 in general colour. In Gynopterus the colour of the back is often 

 suffused with warmer (russet) tinges, sometimes Avith cinnamon, 

 or a tinge between cinnamon and wood-brown, the foreneck, sides 

 of chest, and flanks with chestnut, cinnamon-rufous, or deep hazel 

 (but generally much more so in males than in females). Mego'vops 

 is somewhat paler above, approaching cafe-au-lait, like many 

 Eporaophori ; Sphan-ias nearly greyish hair-brown. Balionycter'is 

 and C7itVo?irtct' are rather darker above than usual, with the head and 

 nape of neck nearly blackish. A well-marked dark brown spinal 

 stripe renders most species of Nyctimene easily distinguishable in 

 colour from all other Fruit-bats ; the stripe is generally narrow 

 (one-fifteenth to one-eighth of the breadth of the back), sometimes 

 obsolescent, sometimes again (^V. ucllo) very broad (one-third of 

 back) ; the general colour of the upperside is sometimes irregularly 

 mottled all over with darker tips to the hairs, as a rule, however, 

 paler than usual in Fruit-bats, fawn-brown, fawn-drab, ashy-drab, 

 ■wood-brown, buff}', or even cream (the palest tinges seen in females 

 of some species). 



Macrorilossince. — Eonyctcris is typically Eousettine in colour ; 

 Megaloglossus and Notopteris dark. In Macroglossus and >Syco- 

 iiycteris the colour of the upperside is lighter, varying from warm 

 russet Front's brown to almost pure wood-brown. Melonycteris is 

 approximately cinnamon above, with small white " epaulettes," 

 nearly seal-brown beneath (an unusual contrast) ; the related 

 Nesonycteris differing only by the pale underparts and the absence 

 of " epaulettes." 



19. Size. 



To show their differences in size the Avhole series of genera of 

 Megachiroptera are arranged below according to the lengths of the 

 forearm (that this list can be only approximately correct is a matter 

 of course, some of the genera being as jet known only from one or 

 a few specimens). The smallest Fruit-bats are but little larger 

 than the very smallest Microchiroptera, the largest greatly surpass 

 in size any form of Microchiroptera. The " expanse " of a Fruit- 

 bat is roughly about six times the length of the forearm (rather 

 more than less). The extent of individual variation is in any Eat 

 usually at least about ten, often twelve per cent., very rarely as 

 much as fifteen to seventeen ; i. e. if in a sutficiently representative 

 series of individuals, all belonging to one species or subspecies, the 

 forearm of the smallest adult individual measures 50 mm., that of 

 the largest will be about 55-56 or a little more, or if the minimum 

 is 150, the maximum will as a rule not be more than 165, rarely 

 as much as 170. 



