44 



on the under parts ; under wing coverts like the rest of the under parts ; crest 

 colored like the back. Bill an undefinable dusky* in the dried specimen ; legs 

 and feet livid gray, (probably greenish or bluish in life) ; membranes black; 

 claws black. 



Dimensions. — (Spec, in Mus. Acad., Phila.) Length about 8-50 ; wing 5-50 ; 

 tail 1-60; chord of culmen -35; gape -60; gonys -25; greatest height of bill 

 •33, greatest width -25 ; tarsus 1-00; middle toe and claw 1-50, outer 1-40, 

 inner 1'25. 



Another specimen, (No. 22,258, Mus. Smiths. Inst.) Wing 5-60 ; tail 1-75 : 

 chord of culmen -40 ; gape -80 ; gonys -40 ; height at base of bill -40 ; width 

 at same point -30 ; legs and toes as in the preceding specimen. 



Three specimens of this species examined : one in the Philadelphia Academy 

 from Kamtschatka, which served as the subject of Mr. Cassin's description in 

 the "Birds of North America;" another in the Smithsonian Institution, (No. 

 22,258,) received from the Bremen Museum, labelled " Phaleris cristatella, 

 (Pall.); Winterkleid ; Kamtschatka;" another also in the Smithsonian, (No. 

 15,805,) labelled "Phaleris cristatella; Bay of Yedo, Japan ; Apr. 1854; eye 

 gray ; iris black ; Rodgers' North Pacific Exploring Expedition." The last 

 mentioned specimen is in a very poor state of preservation, and is a young 

 bird, as evidenced by the short straight crest, directed backwards ; though the 

 bill is nearly perfect in size and shape, aud the general aspect of the bird is 

 precisely that of the adult. The other two specimens are in fine condition, 

 and represent the perfectly mature state. These three include all that are 

 known to exist in any American Museum. It is not a common bird in collec- 

 tions, and is frequently mistaken for the j'oung cristatellus, to which species, 

 however, it bears only a distant and superficial resemblance. 



The bird here described is indubitably the " Dusky Auk " of Pennant, a 

 species more perfectly and satisfactorily described and figured by Dr. Pallas 

 as Alca tctracula. It is a strongly marked species, not distantly allied to, 

 and somewhat resembling cristatellus in everything but the bill, which is of a 

 radically different formation, as will be impressed upon the mind by a 

 perusal and comparison of the descriptions given under head of these species. 

 Tetraculus requires no special comparison with cristatellus or with camlschaticus 

 for the substantiation of its distinctness. .S". Cassini of this paper is the most 

 closely allied species, and might just possibly be confounded by a careless or 

 ignorant observer. The differences will be found under head of the latter. 



The diagnostic points of this species lie chiefly in the small size and pecu- 

 liar shape of the bill (cf. descr.) ; the length of the wings, proportionally 

 greater than in any other species of the genus ; and the greater length of the 

 feet and toes. The wings, tail, feet and toes are about of the same absolute 

 dimensions as those oi cristatellus, although tetraculus is rather a smaller bird. 

 The various shades of the dark color of the plumage are produced by admix- 

 ture of black, brown and gray; there is no pure cinereous or plumbeous on 

 any part of the plumage. 



This is a species which entered at a very early day into ornithological 

 literature, notwithstanding which it has not a single accredited synonym. 

 Its claims to recognition as a valid species, distinct from cristatellus, have not 

 been impugned, except by the learned Director of the Museum of the Pays- 

 Bas. It has been the occasion of no confusion or conflict of opinion among 

 writers, except in those few instances in which it has been erroneously sup- 

 posed to have furnished the subject of Audubon's plate of cristatellus. The 

 most cursory examination of the plate will convince the mind upon this 

 point. Mr. Pennant, in virtue of his "Dusky Auk," which is this species, 

 would have been entitled to the proprietorship of the bird, had he given it a 

 binomial name ; but as it is, Dr. Pallas stands as its lawful sponsor, having 

 christened it Alca tctracula in 1769. 



* Pallas gives its color as " fusco-rubrum ;" Gmelln, as " ex fu9C0-luteseen.s ;" Latham, 

 as " luteo-fuscum." 



