] 14 REVIEW OP 'AMERICAN BIRDS. [PART : 



I have not had the opportunity of examining the M. hambl 

 type of the genus — and have taken the philomela, a near ally, as 

 the standard of reference. This has the general appearance of 

 Gyphorinus, but with still shorter and more rudimentary tail ; a bill 

 less compressed, and elevated at base, and more decurved at tip ; the 

 wings more rounded. The most remarkable peculiarity is seen in 

 the nostrils, which, instead of being single, as is usual among birds, 

 are double, or with two openings. The specimens of philomela do 

 not show the characters very satisfactorily, but one opening is appa- 

 rently crescent-shaped, against the lower side of the nasal groove 

 near the anterior extremity ; the chord of the arc nearly parallel 

 with the commissure. The upper border of the aperture is thus 

 formed by a semi-lunar valvular scale, which may fit down close, 

 leaving only a free rounded aperture behind. Above the posterior 

 end of this opening is another one, shorter, more circular, and 

 against the upper edge of the nasal groove. The septum or bridge 

 between the two is narrow : sometimes reduced to a subjacent ridge, 

 in which case the nasal aperture appears single externally. 



It is possible that I have misinterpreted the indications of the 

 specimens before me, and that the characters of the nostrils is suffi- 

 ciently like that in Gyphorinus not to authorize generic separation. 



The species assigned by Sclater to Microcerculus, excepting C. 

 albigularis, which is a Pheugopedius, form two sections : one with 

 hambla as type, with tail soft and less than half the wings ; the bill 

 higher ; the culmen more elevated and nearly straight above. The 

 second with leucostictus as type : the tail firm, and two-thirds the 

 wing ; the bill still lower than in the last, and more Wren-like ; the 

 nostrils not so much doubly perforate, as with one large oval aper- 

 ture in the anterior extremity of nasal groove divided by a nearly 

 horizontal septum, which shows in the aperture without being 

 united to it, constituting a free septum rather than a bridge ; some- 

 times reaching up to the level of the aperture, and sometimes low 

 and inconspicuous. The tarsal scales are sometimes distinct on the 

 outer side, sometimes completely fused into one with the lateral 

 plates {leucophrys). To this second section, perhaps generic form, 

 I propose to give the name of Heterorhina. 



Microcerculus philomela. 



Cj/phorinus philomela, Salvin, P. Z. S. 1861, 202 (Guatemala) .—ScL. 

 Catal. 1861, 358 {Microcerculus').— La-wr. Ann. N. Y. Lyo. VII, 

 1862 ; Birds Panama, III, no. 311.— Ci/phorinus bamhla. Lawk. Ann. 

 N. Y. Lye. VII, 1861, 320, no. 185 (iris brown). 

 Hab, Guatemala to Isthmus Panama. 



