MR. W. K. PARKER ON THE OSTEOLOGY OF BAL^ENICEPS REX. 345 



geners, from the length and thickness and great mobility of the toes, and from the 

 unusual size (for an Ardeine bird) of the hyposternal processes, it seems fair to con- 

 clude that the Balaeniceps is an oblique link between the Herons and the Rails ; 

 nevertheless the Ralline characters are feeble compared with those that are truly 

 Ardeine. The Balaeniceps is not more mysterious in its relationships than the Flamingo, 

 the Secretary-bird, the Hemipodius, the Sand Grouse (Pterocles), or even than those 

 beautiful little creatures, half Warbler and half Swift, the Swallows and Martins. It 

 will be seen by the table {supra) that the outer toe of Balaeniceps is only half an inch 

 shorter than the middle toe ; this is a disproportionate length of the outer toe as com- 

 pared with what is seen in the Heron, and is equal to what is found in the Jacana 

 (Parra), and the Coot {Fulica). In the Zygodactyles {e.g. the Parrot) the outer toes 

 are long, for turning backwards ; and this elongation of the outer toe is also the rule in 

 the Palmipeds. 



In the Duck the middle toe is only a line longer than the outer ; in the Pelican they 

 are equal ; but in the Cormorant the outer is nine lines longer than the inner toe. This 

 disproportion also occurs in the beautifully lobed feet of the Grebes (e. g. Podiceps rubri- 

 collis) and in the Divers {Colymbus). The middle toes are disproportionately long in the 

 Diurnal Raptores and in the typical Goat-suckers {Caprimulgus) It will be seen from 

 the table that the little arrested toes of the Swift somewhat reverse the order of things, 

 the inner toe being longer than the outer. This little child of the sky has not more than 

 three phalanges in any of its toes ; but the forward-turned hallux has two joints like 

 other birds. 



We have only space here to refer to Dr. Humphrey's invaluable work on the ' Limbs 

 of Vertebrate Animals,' and to say that he is quite opposed to Professor Owen's theory, 

 which makes the scapulse and iliac bones to be ' pleurapophyses:' they are not, in his 

 (Dr. H.'s) opinion, 'pleural,' but ' hcemal.' Like most other anatomists. Dr. Humphrey 

 is entirely opposed to the idea of the scapular arch being the hsemal part of the occipital 

 sclerotome ; he very truly says that the hyoid arch belongs to the occipital segment. 

 (See Dr. Humphrey on 'The Human Skeleton,' p. 597; Report of the British Asso- 

 ciation, 1858, part 2, p. 126 ; and his work on the ' Limbs,' p. 32.) 



Professor Goodsir classes the segments of the limbs of the Vertebrata in the same cate- 

 gory as the 'appendages' or ' epi-pleural spines' — his ' actinapophysis' (oj).ct7., p. 178). 



In recapitulating the structural characters of the Balreniceps, only general remarks 

 will be necessary. Truly, if the Boat-bill had been as yet undiscovered, with its beau- 

 tiful, leaf-like, broadly arched upper jaw, and the little Umbre {Scopus umbretta) with 

 its grooved and hooked beak, we might then have found our task ditScult. Yet even 

 then the highly modified conditions of the bill in other groups would have plentifully 

 supplied us with helpful analogies. Even the families very nearly related to the Herons, 

 as, for instance, the Ibis group, which contains the Spoonbill ; the frailer forms of 

 Waders, yielding us the Avocet ; the Plovers with their knife-billed Oyster-catchers — all 



