02. PUFFIXUS OP1STHOMELAS. 
Pcffin'Ujs Opisthomelas. Coces. Proe. Acad. Nat. Scieu. (1864). p. 139. —Mon. Procell. 
This species, an engraving of the head of which is here given of the natural size, resembles somewhat the P. Anglonm, but is 
much smaller than that species, and has other marks of difference. Cotjes’ diagnosis is as follows : 
P. Puifino obscuro nee perdissimiUs : sed major, vostro longiore, rohustiore, alls pedibmque longioribus, cauda hreviore, minus ? olundata , 
et tectricibus caadce inferior ibm fere omnino fuliginoso-nigris. 
Habitat. South Pacific coast of North America. The specimens were obtained by Mr. Xantus at Cape St. Lucas. Bill along culmen, 
1.40; commissure, 2.00; height at base, .42; wing from the carpus, 9.00; tarsus, 1.80; middle toe and claw, 2.10; tail, 3. (5. 
GENUS NECTRIS. 
93. NECTKIS FULIGINOSUS. ) 
94. — AMAUROSOMA. j 
Yol. II. Plate LXII. 
It is not a very easy matter to always distinguish the various species of “Black Puffins,” as they naturally closely resemble each 
other, and give the impression, that although we can consider them as having received their full growth, still they may not have as yet- 
assumed the adult livery, and therefore only be in a certain stage of plumage incidental to the corresponding bicolor species. 
PTGOPODES. 
FAMILY I.-COLYMBIBJ. 
SUB-FAMILY OOLYMBINiE. 
GENUS COLYMBUS. 
Colymbus. Linn. Syst. Nat. (1735). 
95. COLYMBUS ADAMSI. Yol. II. Plate LXIII. 
96. — PA CIFI C US.— C. ARCTICUS. 
Colymbus Pacificus. Lawk. B. N. Am. p. 889. 
This bird was characterised as distinct by Mr. Lawkexce, who formed his opinion upon two immature specimens. Since his 
description was published, many examples have been received at the Smithsonian Institution, from various collectors in Arctic America, 
in all stages of plumage; and, judging from these, it does not appear to be distinct from C. Arcticus. The color and style of markings 
are precisely similar, and although the bill in some examples is weaker and more slender, yet this member varies very materially among 
individuals from the same locality. 
