No.nie. PEOCEEBINGS OF THE NATIONAL MUSEUM. 497 



its claw decidedly shorter than the digit. Colors, plain brownish, 

 lighter below, with or without tawnv-bufJ" on throat or light wing-bars. 



jSTotwithstaiKliiig the close general resemblance of the species of this 

 geiins to the females of certain Coerebida^ of the genus Bacnis, I have 

 long been convinced that Certhidca belonged to the Mniotiltida? rather 

 than the Coerebidu'. where it had been i>laced by Messrs. Sclater and 

 Salvin. This view of its relationships has been coufirined by an exam- 

 ination of its anatomical structure, made at my suggestion by Mr. F. 

 A. Lucas It is but fair to question, liowever, whether Dacms itself, 

 if examined in the same way, would be found to agree in certain struc- 

 tural cliaracteis with Coo-eha, Arhcloyhina, and Ghfisipfihi, the ty])ical 

 Coerebine forms with which Mr. Lucas' comparison of Ccrthidea was 

 made. 



Range. — Peculiar to the fralapagos Archipelago, where absent, ap- 

 parently, only from diaries and Narborough Islands. (See map.) 



Owing to their extremely plain coloration it is very diflicult to con- 

 struct a " key " to the species of this genus, a difficulty greatly en- 

 hanced by the circumstance that 1 have at the jiresent time examples 

 of only four of tlie eight forms before me, and among these but few 

 specimens in good plumage, the extensive series belonging to Dr. Baur 

 having some time since been returned. The following attempt, there- 

 fore, can only be regarded as provisional. 



KEY TO THE SPECIES OF CERTIIIDKA. 



a'. No wbitisli wing bars. 



6'. Adult males with superciliary stripe and throat oehrareons-lniff or tawny; 

 bill never ( f ) blackish, 

 c'. Adult male with throat and superciliary stripe tawny or tawny ochraceons, 

 remaining under parts dull light bufty. (.James Island.) 



1. ('. oliracea (p. 498). 

 c'. Adult male with throat and superciliary stripe ochrnceous-buff, remain- 

 ing under parts pale butf-yellow. (Indefatigable Island.) 



2. C. sah-iiii (p. .500). 

 b'. Adult males without ochraceous-buff or tawny throat, etc. 



c'. Adults with chin like rest of under parts, or paler, nnd under wing- 

 coveits whitish. 



(IK Billuever(?) black, (Albemarle Island) 3. C. albemarlci (-p. oOO). 



d-. Bill black or blackish, at least iu some breeding adults. 



e'. Bill larger (exposed culmen 0.40 — 0.45) ; upper parts distinctly oliva- 

 ceous, lower parts stronglj' tinged with olive-yellowish. 

 /'. Under parts distinctly buff yellowish, except in worn plumage. 



(Chatham Island) 4. C. htteola (p. 501). 



/^. Under parts buify grayish white or very pale yellowish olive-gray. 



(Abingdon and Bindloe islands) 5. C.fiisca (p. .502). 



e'. Bill smaller (exposed culmen less than 0.40) ; upper parts dull olive- 

 gray, lower parts dull whitish. (Hooil Islan<l.) 



6. C. cinerasceiis (p. 503). 

 C-. Adult with chin and under wing-coverts buff. (Tower Island.) 



7. ('. meiifdlin (p. .504). 



a^. Two whitish wing liands. (Barringtou Island) S. C. bifaticiata ([>.Ml). 



Proc. N. M. vol. xix 3-5 



