62 



Mr. Gray also exlubite(l several specimens of the genus Rhyn- 

 chčea, Cuv., and pointed out from among them tvvo distinct species, 

 which may be thus characterized : 



Rhynch^a Capensis, Sav. Rhynch. remigibus angustis,fasciis 



latis Jlavis sex notatis, injra griseis, 7iigro-vermiculaiis,Jtavoque 



Jasciatis ; secundariarum macula pogonii externi, fascidgue po- 



gonii interni, Jlavis. 



Long. corporis 9| unc. : tarsi, 21^ lin. : digiti unguisque medii, 



20^ lin. 

 Rhynch^a picta. Rhynch. remigibus sublatis, externis Jiavo 

 late 'J -Jasciatis, iiifra griseo nigroque vermiculatis, inlerno obso- 

 letejlavojasciato : secundariuritm apicibus, maculd vltimajascice- 

 Jormi pogonii externi,Jhscidque pogonii interni, albis, 

 Long. corporis 10^ unc. : tarsi, 19^ lin. : digiti medii, 19 lin. 

 The wing-coverts of both species are spotted with yelIow in the 

 young State ; and in the adult statė are metallic olive with black 

 bands. 



Mr. Gray added that the three figiires of birds of this genus \vhich 

 vfere published by BufFon, and vvhich had of late years been re- 

 garded by M, Teniniinck and by M. Cuvier as representing various 

 States of but one species, were none of them sufficiently correct in 

 the details to enable him to refer either of the present species to the 

 representations given in the ' Planches Enluminees;' but tjiat the 

 figure of the Rhynchcca C.cpensis given by Savigny in the ' Oiseaux 

 d'Egypte' [tab. l^. fig. 2.], furnished a faithful representation of 

 the tirst species exhibited by him. He had not, hovvever, obtained 

 this bird from the Cape of Good Hope, his specimens being from 

 India and China. The second species, Rhynchcea pieta, he had re- 

 ceived from Africa as well as from India and China. 



Mr. Vigors called the attention of the Committee to the Frigate- 

 hirdi^Tachypetes Aqinhis, Vieill.), and dwelt upon those peculiarities 

 of its organization which point out its station in the series of na- 

 tūrai aifinities that connect the orders of birds. Although it possesses 

 the vvebbed feet which constitute the technical character of the Na- 

 tatorial Order, the \veakness of its legs and their complete covering 

 of feathers preciude it from employing these members in the šame 

 manner as the typical groups of the Swimming Birds ; while on the 

 other hand its great povvers of wing and tail adapt it for powerful 

 and long-continued flight, and evidently connect it \vith the Rap- 

 torial Order, which it also resembles in its manner of taking its 

 food. It is in fact rather an inhabitant of the air than of the water : 

 and it has been believed that it derives support during its unlimited 

 fliglus not merely from the strength and expansion of its wings and 

 thesingular mechanism of its tail, but also from the buoyant nature 

 of the inflated sac beneath its throat. A proofof the correctness of 

 the opinion that this pouch is really an air-sac, and that it is filled 

 with air, which passing through the bones becomes rarified and ca- 

 pable of imparting a high degree of buoyancy, has recently been 

 obtained from the anatomical notes made by Mr. Collie, late Sur- 



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