PAGE

APPENDIX A.-SPECIES EXAMINED, OF WHICH NO SPECIMENS ARE IN
POSSESSION OF THE SMITHSONIAN INSTITUTION........

............145

APPENDIX B.-SPECIES DESCRIBED BY AUTHORS, BUT OF WHICH NO
SPECIMENS COULD BE OBTAINED ................................................

APPENDIX C.-SPECIES COLLECTED ON THE UNITED STATES AND
MEXICAN BOUNDARY SURVEY BY JOHN H. CLARK AND ARTHUR
SCHOTT, UNDER MAJ. Wм. H. EMORY, AND RECEIVED TOO LATE FOR

INSERTION IN THEIR PROPER PLACES.........

.150

........156

APPENDIX D.-INDEX OF SOURCES FROM WHICH THE SPECIMENS HAVE
BEEN RECEIVED...........................

.....

162

APPENDIX E.-INDEX OF STATES AND TERRITORIES FROM WHICH
SPECIMENS HAVE BEEN RECEIVED..

..........164

PREFACE.

IN the present catalogue it is proposed to present a systematic account of the collection of North American Serpents in the museum of the Smithsonian Institution. In the Appendix will be found such species not in possession of the Institution, as could be borrowed for description, as well as notes on more or less authentic species of which no specimens could be found.

A complete synonomy of all the species has not been attempted, as tending to swell the bulk of a catalogue too much. All those, however, necessary to a proper understanding of the history or character of the species, have been introduced, and all the synonyms quoted have been actually verified by original reference.

Owing to the want of osteological preparations, it has been a difficult task to arrange the genera in a natural succession. In many cases forms are now combined which will hereafter necessarily be widely separated. The almost entire deficiency of modern general works upon the Colubrida, has also been a serious obstacle to any correct idea of a natural system. The forthcoming work of M. M. Duméril will undoubtedly clear up much of the obscurity which now exists. But when systematic writers all carefully avoid the subject of the Ophidians, each waiting for the others to make the first step, the attempt to combine genera by well marked, though perhaps artificial points of relation, will it is hoped be looked upon with indulgence, even after more comprehensive and extended investigations shall render it necessary to break up the combinations here adopted. The collections upon which the original descriptions of the present catalogue have been based are as follows:

SPENCER F. BAIRD. Species from Massachusetts, New York, Ohio, and Pennsylvania.

CHARLES GIRARD. Maine, Massachusetts, and South Carolina.
REV. CHARLES Fox. Species from Eastern Michigan.
DR. P. R. HOY. Species from Eastern Wisconsin.

PROF. L. AGASSIZ. Lake Superior, Lake Huron, and Florida.

JOHN H. CLARK. Maryland, Texas, New Mexico, and Sonora. JOHN VARDEN. District of Columbia and Louisiana.

DR. J. B. BARRATT. Western South Carolina.

MISS CHARLOTTE PAINE and MRS. M. E. DANIEL. Western S. Carolina.

DR. S. B. BARKER. Charleston, S. C.

PROF. F. S. HOLMES and DR. W. J. BURNETT. South Carolina.

R. R. CUYLER and DR. W. L. JONES. Georgia.

D. C. LLOYD. Eastern Mississippi.

DR. B. F. SHUMARD and COL. B. L. C. WAILES. Mississippi. JAMES FAIRIE. Mexico and Western Louisiana.

CAPTS. R. B. MARCY and G. B. MCCLELLAN, U. S. A. Red River, Ark.

FERDINAND LINDHEIMER. Central Texas.

COL. J. D. GRAHAM, U. S. A. The specimens collected while on the U. S. and Mex. Boundary Survey, by Mr. J. H. Clark, viz., in Texas, New Mexico, and Sonora.

MAJ. W. H. EMORY. Specimens collected on the U. S. and Mexican Boundary Survey, by Arthur Schott, at Eagle Pass, Tex., and by J. H. Clark, in Texas and New Mexico.

GEN. S. CHURCHILL, U. S. A. Valley of the Rio Grande.

DR. L. EDWARDS, U. S. A. Northern Mexico.

DR. WM. GAMBEL. New Mexico and California.

DR. JOHN L. LE CONTE. Littoral California.

DR. C. C. BOYLE and J. S. BOWMAN. Central California. DR. A. J. SKILTON. Species collected in California by Henry Moores, Esq.

U. S. EXPLORING EXPEDITION. Littoral California and Oregon. ACADEMY OF NATURAL SCIENCES OF PHILAD. Various unique specimens described by Dr. Holbrook.

BOSTON SOCIETY OF NATURAL HISTORY. California.

Smithsonian Institution,}

January 5, 1853.

SPENCER F. BAIRD,

Assist. Sec. S. I. in charge of Museum.

INTRODUCTION.

EXPLANATION OF TERMS USED.

THE vertical plate is the central one in the middle of the head above, having on each side of it the superciliaries, which form the upper part of the orbit. The two plates behind the vertical are the occipitals; the pair in front of it, the postfrontals. The prefrontals or anterior frontals are situated in front of the postfrontals; and anterior to these and terminating the snout is the rostral. The plates immediately in front of the eye are the anteorbitals; those behind it are the postorbitals. In advance of the anteorbital is the loral, between which and the rostral are the two nasals, with the nostril between them. The upper and lower labials margin the upper and lower jaws. The temporal shields are situated between the upper labials and the occipitals. The inframaxillary or mental scutellæ or shields are just within the lower labials.

The arrangement on the top of the head of one rostral, two pairs of frontals, one vertical with one superciliary on each side, and one pair of occipitals we have considered as typical or normal, from which but few of the genera described vary. Sometimes one plate occupies the place of the two prefrontals, and in some genera a second median plate is seen between the rostral, frontals, and vertical. On the side of the head we have sometimes but one nasal, and sometimes either the loral or the anteorbitals may be wanting. Where the latter condition exists, it is sometimes difficult at first to determine which plate has disappeared. A clue is to be found in the shape of the remaining plate; if this be longitudinal, it is probably the loral; if vertical, or divided into two or more, one above the other, it is to be considered as anteorbital. The loral belongs to the postfrontals, and the anteorbital to the vertical, the posterior edges in the former and

the anterior in the latter generally ranging. Thus, when the ver tical plate is very short, the anteorbital is also short or wanting entirely, and the same relation holds good between the loral and postfrontals.

The specimen whose measurements are first given, unless stated to the contrary, has served as the type of the description, and the first mentioned species is to be considered as the type of the

genus.

Of the five numbers given at the end of the descriptions, the first indicates the number of the abdominal scutellæ from chin to anus. The second is that of the pairs of subcaudal scutella; the third, the dorsal rows or the number of rows of scales around the body (excluding the abdominal series). The fourth number shows the entire length of the animal, and the fifth the length of the tail, in English inches.

In referring to the dorsal rows, the exterior one, or that next the scutellæ, is considered to be the first, unless the contrary is stated.

When there are two numbers separated by the symbol at the beginning of the measurements, the first indicates the number of entire abdominal scutellæ, the latter of those that are bifid or divided. The subcaudal scutellæ are to be considered as divided or in pairs, unless mentioned to the contrary.

In enumerating the number of labial plates, those on one side of the jaws only are to be understood, and the terminal and median one on the symphysis of the upper and lower maxillaries is never included. On the upper jaw that plate is at the end of the snout, and is the rostral.

The descriptions are all based on specimens preserved in alcohol, unless otherwise stated.