SYCALIS.—ACANTHIDOPS. 433 
hardly in a position to speak definitely as to its status with reference to S. luteola. A 
Mexican skin sent to Mr. Sclater by the Parisian dealer Parzudaki formed the basis of 
the original description !; Sumichrast subsequently found it near Orizaba4. It has only 
once been noticed in Guatemala, Salvin having shot a young bird at the edge of some 
high grass on the plain of Duefias in September 1862. There was another specimen 
with it, and the two were feeding on grass-seeds 3. 
Genus Fringillidarum incerte sedis. 
ACANTHIDOPS. 
Acanthidops, Ridgway, Pr. U. 8. Nat. Mus. iv. p. 385 (1882); Scl. Ibis, 1884, p. 241. 
In 1882 Mr. Ridgway described a bird from Costa Rica under the name of Acan- 
thidops bairdi from a specimen sent him by Mr. Zeledon. He considered it to belong 
to the Dendrocolaptide, and to be most nearly related to Automolus, Phacellodromus, 
&c. He sent us the type for inspection, and also a second specimen from the same 
country ; these we carefully examined with Mr. Sclater, who wrote a note on the 
subject in ‘The Ibis’ for 1884. It was proved that Acanthidops has nine and not ten 
primaries, and therefore, according to the prevailing system of classification, it must go 
with the Oscines and not the Tracheophones. Our own impression was that both 
specimens (marked male and female) were young birds in their first full plumage, and 
to this cause was to be attributed the sharpness of the ends of the rectrices. If this 
be so, we may look for a very differently coloured bird in the adult male. At the same 
time, if the suggested relationship to Chrysomitris is a real one, the coloration of the 
adult may be as in C. pinus, and in that case not very different from that of the young. 
Then, again, the exposed nostrils militates against any alliance with Chrysomitris, the 
position suggested for it by Mr. Sclater. 
For the present we suspend our judgment as to the position of Acanthidops, pending 
the receipt of more specimens. 
In the meantime we give the substance of Mr. Ridgway’s description of the genus 
and species :— 
Bill about as long as the middle toe, cuneate in all its profiles, somewhat swollen 
basally, the culmen and lateral outlines decidedly concave in the middle portion ; 
mandibular tomia very strongly inflexed, with a prominent angle near the base, anterior 
to which the edge is decidedly concave; maxillary tomia with a decided notch near the 
base, immediately above the mandibular angle; gonys very long (about equal to the 
exposed portion of the culmen); nostril exposed, small, longitudinal, occupying less 
than the lower half of the nasal fossa. Tarsus a little longer than the middle toe and 
claw, divided into about six plates, but these entirely fused on the outer side, except 
the lower one, which is distinct; lateral toes equal, the points of their claws falling 
BIOL. CENTR.-AMER., Aves, Vol. I., November 1886. 55 
