SPHENICI OR PENGUINS. 211 



The name of this group Sphenici is probably from 

 the Greek sphen a wedge, and has reference, probably, 

 either to the shape of the bill or that of the body, or 

 both. 



Fossil remains of birds are found in the rocks as low 

 down as the Jurassic, inclusive ; and if the so-called 

 " Bird-tracks," in the sandstone of the Connecticut 

 Valley, are really those of birds, then we may say as low 

 down as the Triassic. Both bones and feathers of birds 

 have been found fossil in the Jurassic rocks at Solenhofen. 

 Bavaria ; and the bird represented by these remains has 

 been named the Long-tailed Ancient-Bird (Arckceopteryx 

 tnacrura). This bird had well-developed non-anchylosed 

 metacarpal bones, and a tail of twenty vertebrae, with a 

 row of feathers along each side a pair to each vertebra. 

 The total length of this bird was about two feet. It be- 

 longs to the order of Saurune. 



A large number of species of fossil birds have been de- 

 scribed by Marsh and Cope from the Cretaceous and 

 Tertiary rocks of the United States. These birds repre- 

 sent the Picaritp, iiaptores, Gallinre, Grallatores, and 

 Natatores. (See Professor Marsh's " Synopsis,"" etc., in 

 Dr. Cones' " Key.") 



For aid in the study of North American Birds the student is referred 

 to the " Key to North American Birds" by Elliott Coues ; and to " .-1 

 Jlistori/ of North American Birds " by fc>. F. Buird, T. M. Brewer, and 

 H. Hidgway. 



