NATURAL SCIENCES OP PHILADELPHIA. 299 



Brachyrhamphus hypoleucu3, Xantus. 



Bill slender and slightly curved, about half the length of head. Tarsus scarcely 

 shorter than middle toe. Above dark brownish black, the edges of the feathers 

 with a plumbeous tinge ; the side of neck below, and the axillars with the 

 concealed portion of the sides of the breast, ashy plumbeous. Entire under 

 parts, including tail coverts and inside of the wings, pure white, this color ex- 

 tending on the sides of the head so as to include the eyes, the lids, however, 

 are tinged with dusky ; bill black ; legs apparently reddish in life. 



Length 10 inches, extent 15-80, wing 4-70, tail 1-80, bill above -70, gape 1-20, 

 tarsus -85, middle toe 1-00. 



This specimen is considerably weatherbeaten, and the old feathers of the up- 

 per parts are much worn, and bleached at the edges. The new ones are how- 

 ever as described. 



Notes on a collection of Birds made by Mr. John Xantus, at Cape St. Lucas, 

 Lower California, and now in the Museum of the Smithsonian Institution. 



BY S. F. BAIRD. 



Mr. Xantus, in transmitting to the Smithsonian Institution a collection of ob- 

 jects of Natural History made at Cape St. Lucas, Lower California, in the 

 months of April, May, and June, 1859, has added descriptions of the species 

 which he ascertained to be new by reference to the limited number of works at 

 his command. These all appear to be really nondescript, and a careful com- 

 parison of the entire collection with supposed analogues from the north, 

 shows differences in other species, entitling them to specific rank. 



The examination of the collections of Mr. Xantus has proved of very great 

 interest in elucidating the zoological peculiarities of the Cape, and especially in 

 showing that its fauna is almost identical with that of the Gila River, and to a 

 certain extent with that of the Rio Grande. It is an important fact also, that 

 while these relationships are exceedingly intimate, there is almost none to the 

 coast fauna of Upper California. As the birds were all collected during the 

 spring months, after the migrating species had passed northward, they may be 

 considered as especially characterizing the region. An examination of the list 

 will show that of the forty- two kinds thus far received from Mr. Xantus, seven, 

 or one-sixth, are peculiar to the Cape and probably new, while but two of the 

 land birds which characterize the Pacific region of upper California are found 

 there, all the other species being either distributed generally over the whole 

 United States, or belonging especially to the Gila or Rio Grande regions, sepa- 

 rately or collectively, and to that of the Southern Rocky Mountains. 



Similar conclusions are to be derived from an examination of the other land 

 vertebrates. The most characteristic mammal is the Spermopkilus harrisii, 

 heretofore only found in the Colorado desert. The Perognathus penecillatus, 

 another Colorado species, is also met with. The Macrotus calif ornicus, a leaf- 

 nosed bat, heretofore only known from a single specimen taken at Fort Yuma, 

 is very abundant. Lepus californicus and trowbridgii, Mephitis bicolor and Ves- 

 pertilio pallidus, Le Conte, appear to be species common to the Cape and to 

 Western Upper California, the two latter occurring also in Texas. 



In the Reptilia, also, very interesting facts are to be observed. Here, as far 

 as can be ascertained by a hasty examination, out of about twelve species of 

 Saurians, and as many Ophidians, not one is found in Upper California, the 

 species consisting (with the exception of a few new ones) of such as Dipsosaurus 

 dorsalis, Uta ornata and stansburiana, Sceloporus scalaris, Callisanrus ventralis, 

 Stenodactylus variegatus, frc. There is a Phrynosoma very similar to the " corona- 

 turn" of Upper California, but quite distinct. There is also a very large 



1859.] 



