02 



NATURAL HISTORY OF BIRDS. 



them with llii.' vomer ]iointe<l in front, have two carolnls and altersliaft ; they all pos- 

 sess the ambiens muscle, as also the semitendinosus, and the accessory sliji of the 

 latter. 



(ienerally, the ' wailers' may be said to be littoral in their habits, only few of tlicm 

 being exclusively terrestrial, avoiding the water as carefully as most of them do the 

 oj)cn ocean; the sliores of the sea and the lakes, the banks of the rivers, and the 

 swaui]is anil marshes are inhabited by some form of this ]iolymor|phic yrouji, the mem- 

 bers of which are distributed all over the globe, from the ii-y neighborhood of the 

 poles to the hottest regions under the equatorial sun. 



One of the most interesting of all the many interesting and )iuzzling forms of this 

 order are the birds which compose the super-family CIIIO\()II)EiE. The early 

 sysfematists realized the isolated position of the sheath-bills, and gave the grouji 

 set aside for them various names, as Vaginati, Coleoramphi, etc., the curiously con- 

 structed bill being the most obvious character. But in regard to the relative taxo- 

 nomic rank of the group, opinions have differed widely, as it has been referred to 

 every ])0ssible grade from a mere genus to an order. Equally variable have been the 

 o]iinions of ornithologists as to their relationshijt, since some have refen-ed them to 

 the CJallinaceous birds, others to the I-ongipenncs near the gulls, others again to the 

 Gralla). The former based their conclusions chiefly upon the most external characters 

 and the alleged gallinaceous habits of the birds, the latter took chiefly the internal 

 .anatomy into consideration. And, indeed, it seems as if both those advocating their 

 place near the gulls, and those urging their affinity to the plovers and oyster-catchers, 

 arc right, for the sheatli-bills arc so intermediate between them that it is difficult to 

 say where they should rather go, though the -present writer is inclined to ]ilace them 

 with the latter. In fact they are hanlly well ]>laced before both Laroidere and Chara- 

 drioidea' are united with the Chionoidea? in the same order. 



Notwithstanding the external difference between the incmliers 

 of the two families com])osing this super-family, their nnitual rela- 

 tionship lias been understood for a considerable length of time, 

 chiefly, we think, on the authority of Jionapartc, who as early .as 

 183"2 miited them in one family. Of characters which both 

 Chionidie and Tliinocorida' have in common, it may be mentioned 

 that they are schizorhinal, that they lack occipital foramina and 

 basipterygoid processes, but have su]ira-t)ibital impressions, that the 

 ambiens muscle, as Avell as the femoro-ca\idai, with the acces- 

 sory, and the semitendinosus, with its accessory sli|) are jiresent 

 (ABXY-f), that they have two carotids, etc. The most remark- 

 able internal feature is, ]perliaps, the shape of the vomer, which 

 is broad and rounded in front, while in other allied forms, Ceco- 

 morphons and Charadriomorjihous, that bone is jiointed or bifid 

 anteriorly. The palate, indeed, in this and some other resjiects, 

 shows some resemblance to that of the Passerine birds, this being 

 especially the case with the Thinocorine jialate. in which the vomer 

 is connected with the nasal cartilages in a manner recalling that 

 of the yEgitliognatha'. 



Like many, not to say most, of those perplexing forms which ie]iresenl the earlier 

 offshoots, or remain as the last survivors of groups once numerous but long since 

 decimated, the Ciiionid.k, only twt> species, inhabit islands in the vast oceans of t^ie 



Fio. 30. 

 fnco of HkuU of At- 

 lat/is t/raifi. 



