1852.) 187 
result of an attempt to arrange them, and to reconcile their synonymes, in a 
second edition of my catalogue of the Strig¢de@ in our collection. ; 
Of the interesting little bird at present described, two specimens, male and 
female, are in a collection made principally on the coasts of Angola and Ben- 
guela, during a recent voyage of the U.S. brig Perry, and presented to the 
Academy by A. A. Henderson, M. D., Surgeon U. 8. Navy, who was attached 
to that vessel as medical officer. I have taken the liberty of dedicating it to 
Dr. Henderson as a slight testimonial to his profound and varied scientific 
acquirements, and as a memento of our long-continued and pleasant friendship. 
7. Larus Heermanni, nobis. 
Form. Bill rather long and slender, wings very long, extending beyond the 
tail, first primary slightly longest ; tail truncate or slightly emarginate. 
Dimensions. Total length of skin from tip of bill to end of tail about 174 
inches, wing 133, tail 5}, bill from the angle of the mouth to the tip 23 inches. 
Colors. Billred, both mandibles tipped with black; feet and legs dark; head 
white, which color gradually fades into an ashy lead color, enveloping the entire 
body above and below; darker above and on the wings, and paler beneath. 
Secondaries tipped with white, which forms an oblique bar of white on the wing. 
Superior coverts of the tail pale cinereous, nearly white. Quills and tail 
brownish black, the latter tipped with white. Shafts of the two first primaries 
white on the inferior surface of the wing. 
Young. Rather smaller, total length about 16 inches, wing 13, tail 5, bill 
from the angle of the mouth 24 inches. Entire plumage brown, dark on the 
head and paler on the under surface of the body, quills and tail feathers brownish 
black, the latter narrowly edged at the tip with white. 
Hab. Coast of California at San Diego, discovered by A. L. Heermann, M.D. 
Oés. This beautiful gull appears to belong to a group of species comprising 
Larus Belcheri, Vigors, L. erythrorynchus, Gould, and others, all of which in- 
habit the shores of the Pacific ocean. It is most nearly related to L. Belchert, 
but is not so large, and has the head pure white, which is not the case in that 
species. In the description of the latter (in Zool. Jour. iv. p. 328,) the rump 
is described as white; in the present bird the rump is dark ashy, but the su- 
perior coverts of the tail nearly white, and in the young bird they are dark 
brown. 
I have dedicated this handsome species to my friend Dr. Heermann, as a token 
of acknowledgement due to his accomplishments as a naturalist, and his great 
perseverance and success as a scientific traveller. 
8. Mergus amertcanus, nobis. _ Wilson’s Am. Orn. viii. pl. 68. Aud. B. of 
Am. pl. 331. 
Obs. I propose this name for the common bird which has hitherto been re- 
garded as identical with the European species well known as Mergus Mergan- 
ser, Linn. It is, however, specifically quite distinct. In the American bird 
the prolonged feathers of the head are almost restricted to the ecciput and neck 
behind, but in that of Europe they commence almost at the base of the bill, and. 
are erectile and crest-like. On the large wing coverts in the American species 
there is always an exposed and conspicuous bar of black, which, in the Euro- 
pean species, is entirely concealed by the lesser coverts. This character is suffi- 
cient for the purpose of the practical recognition of the twe species in all the 
specimens that I have ever examined, and may be observed on comparing any 
plates of the two species that I have seen, but especially Wilson Am. Orn. viii. 
pl. 68; Aud. B. of Am. pl. 331; Selby, Ii. pl. 53; Gould B. of Eur. v. pl. 39; 
and Korner Skandinaviska Foglar pl. 57. 
9. Anser parvipes, nobis. 
Form. Generally resembling A. canadensis, Linn., but not so large, and with 
the bill and feet much smaller, the Iatter being not. much more than half the 
size of that species. Upper mandible not so strongly serrated on its edges, 
tarsi slender, tail rather fully Per og Possibly a Bernicla. 
