( 266 ) 



Mrtatarsus : 

 Length 



Width of upper end 

 „ lower end 



„ shaft . 

 Length of hallux . 

 „ 2nd digit 



3rd „ 

 4th „ 



In the case of Pa/aeo^/?ft?ias all these measurements are taken from the nearly 

 complete skeleton. Examination of a number of isolated bones shows that a con- 

 siderable range of variation in size occurs. In the ease of the femur the average 

 length of twelve specimens was 84, the maximum being 91, the minimum 80; the 

 average of twelve tibiae 162, maximum 169, minimum 155 ; average of thirty metatarsi 

 91 '3 mm., maximum 99, minimum 85. If the length of the tibiae be taken as 100, 

 the lengths of the femur au'l metatarsus will be approximately represented by 52 and 

 58'5 respectively. 



The hallux, as already mentioned, is somewhat reduced ; the degree to which 

 this reduction has taken place may be roughly estimated by taking the length of the 

 metatarsus as 100, and rei)resenting th." length of the hallux as a percentage of it. 

 If this is done, the hind-toe of Palaeolimnas will be 52, that of F. atra 62, and that 

 of F. cristata 60 nearly. 



If the sum of the lengths of the bones of the leg be taken as 100, then the sum 

 of the lengths of the humerus, radius, and metacarpus will be about 64. In F. aim 

 the wing is very considerably longer in proportion to the leg, being represented by 82. 

 Of course these proportions cannot be taken as giving any exact measure of the flying 

 power, since the length of the leg may have increased without a proportionate addition 

 to the bulk of the body, and indeed, taking into account the considerable size of the 

 sternal keel and the deep impression of the insertion of the pedoralis ninjor on the 

 crest of the humerus, it seems probable that Palaeolim/iias may still have been 

 capable of heavy flight for short distances. 



OSTEOLOGY OF NESOLIMNAS (Gen. Nov.) DIEFFENBAGHIl (Gray). 



During a visit to the Chatham Islands aliout 1840 Dr. Dieflfenbach obtained 

 a single s|)ecimen of a flightless rail, which was afterwards described by J. E. Gray * 

 under the name Ralliis dieffenbachii. The same writer afterwards referred this bird 

 to the genus Ocyclromus, and by Bonaparte it was included in Ilypotaenidia, a position 

 which Gray himself subsequently adopted for it. 



In 1872 llutton t gave an account of another flightless rail of smaller size, also 

 peculiar to the Chatham Islands. This he first called Rallvus 'nwdestua, but after- 

 wards j: established a new genus, Caha!}(,s, for its reception. This species has been 

 regarded by some writers as the young of Dieifenbach's bird ; but, as Huttou showed 

 in the paper cited below, this could not be the case. His opinion having been 

 endonsed by several writers, including Salvadori, P'orbes, and Murie, this view has 

 now been abandoned. This being the case, it becomes necessary to consider the 



• Dieftenbach's Trarels in J\'ew Zcalaiul, II. Apiicndix, p. 197 (1S43). 



t ////.', p. 247 (1H72). 



X ■rrant. .V. Z. InMt. Vol. VI. p. 108 (1872). 



