LIBRARY OF R. D LACOE. For the Promotion of Research in RETURN TO SMITHSONIAN INSTITUTION WASHINGTON, D. C. Pd | : x ¢ P . yy , e & At} ~~ “oh a are). lem P . ‘ P S we @. 3 @ b . \ ear PY \ Wie Aa . ® ‘os Ne ose ger % . * ee. ¢ " q . ve ee fS i 4 . Pe ®. 44 28 ® = ° : 2 y ae -. 2 oe Se~~ ee Otis of » , BS < , & a-* PN a : ; Nowe J @t- J eon ie f S yr af ey | VAN RA Bs ON, Vaal eS a? ‘> ral ey Lo ee SS ad a Prank 5 ~- La. thes ss ind : ee eh Rati, i i ie my Ly Te 2s Cael aritae get a Kies Seay nt ri = ae, era cAsS. | DEPARTMENT OF THE INTERIOR. REPORT Or THE UNITED STATES GEOLOGICAL SURVEY THE TERRITORIES. eS Wee) TSICAC SID ING, UNITED STATES GEOLOGIST-IN-CHARGE. OU 1 WASHTINGTON: GOVERNMENT PRINTING OFFICE. 1875. Vertebrate Pa} USS Nationa eantology Museum ; LETTER TO THE SECRETARY. OFFICE OF THE UNITED STATES GEOLOGICAL SURVEY OF THE TERRITORIES, Washington, D. C., October 5, 1875. Sir: The very valuable memoir, by Prof. E. D. Cope, on the “ Verte- brata of the Cretaceous Formations of the West,” is respectfully submitted for your approval and for publication. ‘The great interest which has been excited among the people, as well as among scientific men, by the discoveries of the remarkable extinct vertebrate remains, within a few years past, in the num- erous ancient lake-basins of the West, will render the publication very opportune at this time, and one of great value to the intelligent world. Asa contribution of materials toward the solution of the numerous problems involved in the geological structure of our great West, as well as the unfold- ing of its ancient life, it must take the highest rank. Jn a certain sense, Paleontology, or the history of ancient organic remains, lies at the very foundation of geological science. It oftentimes stands as the arbiter on doubtful questions, and is a very important aid to the stratigrapher in unfolding the age of strata, and in fixing the great time-boundaries of groups, as well as divisions or subdivisions. No geological survey can be considered complete without its codperation. It has been with this idea that so much of the strength of the survey has been given to this department. So far as the opinions expressed by the author in regard to the age of the Lignitic group are concerned, he alone is responsible to the scientific world. In all the publications of the survey under my charge, prepared by collaborators of established reputation, I have thought it best to permit the broadest latitude in the expression of opinions, whether they harmonize with my own conclusions or not. While Professor Cope reads, in the teachings of the extinct vertebrate fauna of the Liguitic group, its Cretaceous age, Pro- iii hy fessor Lesquereux, with equal sincerity and force, decides, from the lessons of the fossil vegetation, that it belongs to the Tertiary epoch. The present volume will be followed in due time by two others by the same author, on the Vertebrata of the Tertiary Lake-Basins of the West. I have the honor to be, your obedient servant, F. V. HAYDEN, United States Geologist. Hon. B. R. Cowen, Acting Secretary of the Interior. \/ + Dy UNITED STATES GEOLOGICAL SURVEY OF THE TERRITORIES. es A esata Ss THE VERTEBRATA CRETACEOUS FORMATIONS aa Wels By E. D. COPE. FEB 18 1987 LisRARIES WASHINGTON: GOVERNMENT PRINTING OFFIOE. 1875. CONTENTS. - é Page. Mettertoverotessorsbay.d enbeccmas see massce eases secession eee ees a inleapanicinieioreyorsieieiets sieine ee 5 Introduction: on the significance of paleontological science ........---..----...---- 22-2) eee 7 PART I. On the classification and distribution of the Cretaceous deposits of the West...-. ....-----.--- 15 PART Il. Descriptions of the Cretaceous Vertebrata of the West..-...-..--.-----..----- .-----.2-2 eee 42 iieDescripriontofithelocalitiesjandgrannage sesame seco cceesecetncee ae ceerereaess 42 2. Literature of the Reptilia. ...-...-..----. oh0 9650 nogeun oSUDndocoK Gaon eno 6ece BabN AaeS 61 3. Descriptions of the Reptilia... -- - Be eveke Rte ays oie eat ice ee CEE SIE EC cie eee CE 53 AMiteravure Olt He Wishes scomGemes ce eeeee je semcicey sec qsee wae eae ieenl eae ee ise e 179 om Description siorechey ish esi sep: ree tee se amr eels elas ees ee eres Aamo resem oe 180 PART III. Synopsis of the known Cretaceous Vertebrata of North America. ..-.-.-.-....--....--.......-- 245 LIST OF WOOD-CUTS. Fig. 1. Diagram of teeth of Cionodon arctatus, page 59. . Sketch of bones of Protostega giges, taken at time of discovery, page 99. . Costal bones of a young Testudo polyphemus, page 112. . Ramus of lower jaw of Clidastes propython, page 122. . Ramus of Loxocemus bicolor, page 122. . Ramus of Eryx johnii, page 122. . Pelvis and adjacent vertebrie of Liodon proriger, as exposed in the matrix, page 171. . Cranium of Portheus molossus, page 184. . Femoral bones and ventral fin of a Portheus, from above ; a, from below; b, from the side, page 192. . Seapula, ete., and base of pectoral fin of Pelecopterus chirurgus, Cope, page 244 B. m Ww 0 on Ooms nan ran i=) PHILADELPHIA, January 20, 1875. Sir: The accompanying pages embrace my final report on the vertebrate paleontology of the Cretaceous formations of the West. The greater number of species described has been derived from the beds of the Niobrara (No. 3) and Fort Union (No. 6) epochs. The material has been obtained from the explorations in Kansas by the writer in 1871; from similar explorations in Kansas by Prof. B. F. Mudge in the years 1870 and 1872; from the explora- tions by the writer in Wyoming in connection with the United States Geolo- gical Survey in 1872; and from a similar expedition in Colorado in 1873. I wish to express here my indebtedness to various friends who have assisted me on these occasions; especially to General John Pope, commanding the Department of the Smoky Hill, and Captains Butler and Lyman, and Dr. King, stationed at Fort Wallace at the time of my expedition in 1871; to Dr. John H. Janeway, United States Army, of Fort Hays, and Profs. B. F. Mudge and George Merrill, of Kansas, for invaluable specimens of the fossils of the Niobrara group; and to Capt. E. O. Clift, Dr. Joseph Corson, and Judge - W. E. Carter, of Fort Bridger, Wyoming, for many kindnesses. I am also under obligations to George M. Dawson, geologist of the British North Amer- ican Boundary Commission, for the opportunity of examining fossils from the Fort Union beds of British America; and to the Smithsonian Institution for facilities in the use of specimens and books. Where it has been possible to throw light on questions of stratigraphy, this subject has also been touched upon. Tam. with much esteem, K. D. COPE, Paleontologist. Dr. F. V. Haypen, Director of the U. 8. Geologwal Survey of the Territories. INTRODUCTION. ON THE GENERAL SIGNIFICANCE OF THE SCIENCE OF PALEONTOLOGY. le Paleontology is an exact science. It embraces generalizations or laws obtained by induction, which may be deductively applied to the unknown. Its first law is an illustration of the uniformity of nature’s methods, namely, the law of the persistence of type. An organized structure once created, and existing under circumstances not hostile to its working, is adhered to with the greatest fidelity, and extended in time and space. This constant law is the key to this as to the other biological sciences, and occasionally surprises the student of evolutionistic proclivities. On this basis, the possibility of reconstruction of the extinct forms of the past will always rest; and the cer- tainty of the law is unconsciously admitted by every paleontologist who determines, names, or classifies a fossil from anything less than a perfect specimen. It is assumed every day, and universally allowed, although occa- sionally even an expert is found who sometimes questions it, and still more frequently an inexpert who does not read nature aright. The application of the law is, however, various as the given terms, 7. ¢., the remains preserved, differ in significance. Thus, to illustrate, certain parts are common to all stoves, and distinguish them from all other articles of furni- ture; but certain other parts not only belong to a stove, but mark a given pattern of stove, since they belong only to it. A still more minute range of appearances is found only in one man’s make of stoves, and others in that of another man. Hence, a person acquainted with stoves, sewing-machines, &c., can readily determine the origin of a very small part by referring it to its proper kind and make. The application of this law of persistence presupposes a knowledge of the pattern as essential to its deductive application. Hence, a difficulty at once suggests itself as arising when a portion of an animal belonging to a new 8 pattern is discovered. That patterns quite distinct from those known to zodl- ogists have existed in past ages has been well proven by paleontologists. How can the structures of a species of such a kind be inferred from a frag- ment! Another law equally true with that of persistence has been developed from the facts, but it is much more difficult of application. This is the one already defined by the writer’ under the name of the law of “successional relation.” It is absolutely certain that the types of nature, whether pri- mary or subordinate, form series of steps passing from one condition of rela- tions to another. The natural deduction is, that if a portion of an animal exhibits a form intermediate between two known forms or types, the remainder of the animal’s structure possesses the same kind of intermediacy. This law is tacitly admitted, and employed by paleontologists; but there is a diffi- culty of application in consequence of the existence of other laws now to be considered. The first difficulty arises from our possible ignorance of one terminus of the series or line in which our fossil represents a stage. This objection is more theoretical than real, because the living classes and orders are the struc- tural extremes of the lines of succession; nevertheless, among divisions of lesser range, many have reached their culmination, and disappeared in times past. ‘These points of culmination must be known in order to ascertain the direction of the succession. Every discovery, however, is not that of an advanced position on such lines; intermediate positions being necessarily more numerous than termini. Hence, this difficulty is of only occasional recurrence. The preceding considerations all express different phases of the law of uniformity. I now refer to the law of variation, which is in apparent conflict with it. It is the law which expresses evolution as opposed to persistence of types. It especially limits the application of the last law, that of uniformity in succession; 7. ¢@., that when one portion of structure occupies a position intermediate between two already known types, the remaining parts of the same animal or system of organs will occupy the same relation of structure to the corresponding parts of the known. This is not uniformly true. The law of variation intervenes, which states that it may occur that, while one part of an organization occupies a relation of intermediacy, the other parts do not exhibit exactly the same relation. It is by the unequal mingling of structural points that new lines of succession are marked out. Thus it is ‘Penn Monthly Magazine, 18727 p. 229. ) that the power of reconstruction from fragments 1s limited, but not sufficiently so as to justify the epithet ‘‘ pretension,” which has been applied to the claim made. Besides, two other laws remain, which are of great importance to the paleontologist. Illustrations of the preceding laws may first be given. If a fragment of an animal be found, which contains a certain type of teeth known as the true selenodont, it is certain, in accordance with the law of uniformity of type, that the first-bone of the hind foot of that animal (the astragalus) possessed two pulley-grooved faces, one above and one below, and not one only, as in most animals; also, that the lower pulley-face was succeeded by two sub- equal toes, and that the lateral toes were either reduced in form or wanting. There is no mechanical relation between the structures of the teeth and foot ; their accordance is simply a fact of type of a selenodont Artiodactyle. Again, if I find a portion of a foot which presents a joint between the first and second rows of bones which form the sole, I am absolutely certain that the animal had the two outer ear-bones external to the skull, forming a part of the lower jaw and the connecting-rod by which the latter is attached to the skull. This is a type-law of the bird and reptile. Again, if I find a part of a foot of the structure just named, where the first row of bones of the sole is united into one mass, and closely embraces the leg-bone without being continuously united, I know that I have an animal with teeth, with a very long hip-bone and a very long series of united vertebra (or sacrum) resting upon it—in other words, a Dinosaurian. The law of uniformity in successional relation is well illustrated by the genus Loxolophodon. The first bone of the foot (astragalus) of this animal exhibits characters intermediate between that of the elephants (Proboscidia) and odd-toed hoofed mammals (example, tapir) ; the remainder of the skeleton does the same; the neck-vertebree are similar to those of the former, while portions of the skull resemble corresponding ones of the latter. The foot of a dinosaur is intermediate between that of a reptile and that of a bird; so are the sacrum and pelvis. The sternum of a frog of the family Discoglosside is intermediate between those of ordinary frogs’and salamanders; so are the vertebre and ribs. Examples of the limitation of the latter rule are still more numerous. They may be produced from the three cases cited. Thus, in the dinosaur, it ‘Represented by a Ruminant. ) « aC 10 might once have been said that the jaws did not partake of the intermediacy, because they all present teeth, and are never smooth, like those of birds. Yet birds with teeth have recently been discovered, which deprives us of the use of this character as a definition. In the discoglossid frog, the cranium is not intermediate in structure between the frog and salamander, but is that of a trog. In the Lexolophodon, the toothless front of the upper jaw is not a general character of either of the orders between which it stands. These difficulties arise from the existence of the subordinate variations or subtypes of a general or major pattern, and, for their resolution, require only a new application of the first law of uniformity on the lower plane. If the subcharacters defining the subpattern be known, the existence of one presupposes that of the others. The structure of ‘an artiodactyle astragalus will not enable me to infer the character of the incisor-teeth of the animal ; for this I require some other more minutely-correlated portion. So I can infer the ribs and vertebrae from the sternum of the discoglossid frog, but not the cranium; for this I require some part correlated with discoglossid char- acters only, and not only significant of the relations to the orders of Batra- chians, as are the characters mentioned, although it happens, by the accident of discovery, that none but such frogs are known to possess them to-day. The two laws which further aid the deductions of the paleontologist are those of mechanical relations and of embryonic parallelism. One structure requires another in order that an animal be viable. Thus, long legs in a grazer presuppose a long neck to enable it to reach the ground with its lips. Hooked claws presuppose carnassial teeth or a hooked beak. For a horizontal body to be properly poised on two legs instead of four, the weight of the viscera must be transferred backward, and the anterior regions of the body lightened. This we find to be the case with birds and Dinosauria. The lower bones of the pelvis, with the contained organs, are thrown backward, while the fore- limbs are lightened and the head reduced in proportionate (not absolute) size. The parallelism of types with transient embryonic conditions of cther types, aids the paleontologist essentially in the classification or proper location of a specimen. Its relation to known series must be first determined, as this obviously precedes in reconstruction all application of the law of uniformity. Such reference having been made, either to a new series or to a place ina known series, the considerations heretofore adduced come into view, but not sooner. Hence, the law of parallelism is as essential to the paleontologist, as it is all-pervading and all-expressive of nature itsel!- 11 Il. Paleontology in its relation to geology is as yet partially empirical. Thus, while its indications are definite for one locality, they have not identical significance for all localities on the earth’s surface. The lower we descend in the scale of being, the more uniform over great areas are its phenomena; but, among higher animals, especially vertebrates, the greater the geographical peculiarities as compared with the stratigraphical. Professor Agassiz once said that the existing geographical faunze are more distinct than the extinct faunze.of two consecutive epochs of geologic time; a statement justified by many facts. Hence, it has been believed by some, that fossil vertebrates cannot furnish conclusive evidence of the age of the rock-strata in which they occur; for, say they, we have to-day existing on the Australian continent, animals that approach more nearly to those found fossil in the Jurassic forma- tious of Europe than to any now living on the latter continent ; so that, were Australia to be presently submerged and her strata and fossils again brought to light, the paleontologist would assert, that the sun had not shone on that land since the days of the Jura. And so he would were he not at the same time a zodlogist; just as the bare zodlogist would err in the opposite direction of assuming the modern age of the European Jurassic beds, because they contain the living types of Australia. Thus, a foundation-fact of zodlogy properly applied is essential to the paleontologist, namely, that the earth now presents four or more distinct faunal areas, the more prominent among which are the Australian, the South American, and the temperate lands of the northern hemisphere. Each of these possesses many peculiar forms of life not now found elsewhere. Has this distinction always prevailed? Paleon- tology answers decidedly in the affirmative, so far as extinct mammalia are concerned. There seems to be no doubt that the faunal distinctions have a very ancient origin, and are therefore to be first considered when estimating the age of strata from the contained mammalian remains. ‘The explanation of this diversity is not yet attainable; but an important advance has been made by the discovery of the great similarity between the extinct forms of the northern hemisphere and the living or more modern ones of the southern hemisphere faunee. The Jurassic character of much of the Australian fauna is known, while prevalent types of South America and Africa can be shown to haye much relation to Kocene types of the north. In North America and Europe, tapirs, opossums, coatis, civets, kinkajous, lemurs, and allies of the 12 toxodonts belong to the Eocene; now these animals characterize the southern continental life, or, as is the case with toxodonts, have but recently become extinct there. This mode of defining those faune is not, however, exact, since many modern types have found their way into them, especially in the case of Africa. How, then, is life significant of chronological station in the earth’s strata? Since very many forms of animals are so widely spread and at the same time so distinctly limited in range on the earth’s surface to-day, the same order must have prevailed in past time, and have been of equal significance. : That this law of uniformity has prevailed in the past as in the present is amply proven by the paleontology of a single zodlogical area taken by itself! The apparition of types over the northern land-area has been nearly universal. This fact has only been placed within our reach by modern investigations in North America; for, until the sister continent of Kurope-Asia was explored, no one could be sure what degree of individual peculiarity her extinct life might present. Now it is certain that the succession of Tertiary beds was mutually similar, and that the contemporaneous deposits contained in a large degree similar life, and that intermediate stages of the one can be properly intercalated in the vacant interspaces of the other. The resemblances be- tween the Lower Eocenes of New Mexico and Wyoming and that of France are marked; similarity between the Pliocenes of the respective continents is evident. Descending in the scale, the parallels between the North American and New Zealand Cretaceous are very apparent, and the faunee of the Caro- linian and Wiirtembergian Trias were the same. The interruptions in the record of life marked by the appearance of great land-areas near the close of the Carboniferous and Cretaceous periods are universally observed in the zoological areas of the northern hemisphere, or Arctogeea. The close of the Cretaceous everywhere saw the end of ammonites, rudistes, and sauroptery- gian and dinosaurian reptiles, in spite, in North America at least, of physical continuity of deposits. Was this succession of interruptions of life universal over the globe, and do these trenchant lines justify the old assumption of repeated destructions and re-creations of animal life? The former question has already been answered in the negative by the explanation of the characters of the existing faunze of the southern hemisphere, where ancient types still remain in con- siderable numbers. Moreover, some of the later periods of hoth North 13 America and Europe are characterized by a large predominance of forms of the corresponding southern continent. It is, indeed, evident that migration from the one continent to the other has taken place, and is amply sufficient to account for the abrupt changes in the life of each, without necessitating the intervention of creative acts. If glacial periods be dependent on cosmic movements, the increased obliquity of the earth’s axis to the sun, at periods 25,000 years apart, due to the same causes as precession, would cause a cor- responding alternation of cold periods in the opposite hemispheres. This is well known as a most potent cause of migration and extinction, and the known relations of the faunze would thus result from a greater or less alter- nate invasion of the one hemisphere by the life of the other. But within the great time-boundaries are distinct land-faunze whose striking distinction may not thus be accounted for. Thus, the Miocene and Loup Fork faunze of Western America are entirely distinct, but with corre- sponding members. The alternate presence and absence of water-areas adapted for the preservation of the remains of the animals will abundantly account for such minor interruptions. Such changing topography is well known as due to the slow vertical oscillations of the earth’s crust. The original question, the exactitude of the chronological significance of structural types, has been momentarily held in abeyance. Is paleontology a science so far exact as to furnish a chronological scale of terrestrial strata? The admission that the known Tertiary faunee, for instance, are but fragments of a continuous succession, would appear to invalidate any such claim. It would indicate that the restriction of a given type to a given horizon is only a matter of discovery, and that another accident may at any time give it a new range. This objection has but little weight. Fragments though they be, nearly-related formations, as the Tertiaries, are obviously the visible portions of a serial succession of life. Like the bright lines in a spectrum, the order is not disturbed by the temporary obliteration of a part of the colors, but the visible portions indicate the relations of the component parts with infallible certainty. The more universal the physical interruption, the more far-reach- ing the break in the succession of life in any one locality, the greater is the significance of remains of animals as indication of relation in time. The change of faunze in Arctogzea at the close of the Cretaceous is a case in point. A dinosaur, sauropterygian, ammonite, or rudist are as definite indicators of 14 he lite that preceded the change as a tapir or civet-like carnivore is of the age that followed. : . It has been stated that the life of the present period in the southern hemisphere is not homogeneous. The same is true though in a less degree of the northern. Thus, if we include India in the latter, the elephant is a Pliocene form, and the true rhinoceros Upper Miocene. In the northern hemisphere, the dogs are Miocene. In North America, the opossum, and probably the raccoon, are Eocene; the wolves and foxes are Miocene, and the weasels Pliocene. Perhaps, the cats first appeared in our Pliocene. Com- paratively few mammalian types mark, by their origin, the latest geologic epochs. Such are the ruminants, as deer, and oxen, with the true horses, which all commence in the Upper Pliocene of Arctogaea. Finally, man alone signalizes the last or glacial period, and is to reach his culmination in the ages that intervene between that great time-boundary and one to come. Thus, a certain proportion only of the life of a given epoch is character- istic of it, that is, originates in it; the remaining members being legacies from preceding ages. Hence, the latest forms of life embraced in an extinct fauna are the true indicators of the chronological relations of that fauna. 1B yay des GD ike THE CLASSIFICATION AND DISTRIBUTION OF THE CRETA- CEOUS DEPOSITS. Messrs. Meek and Hayden have classified the vast thickness of the Cre- taceous formations of the West from observation of the section made by the Missouri River from near its sources to the point where it enters the Carbon- iferous strata of Eastern Kansas. This classification has been found by Dr. Hayden to be applicable to the exposures of the rocks of this period along the eastern base of the Rocky Mountains; and I may add that an examina- tion of the western flank of the same mountain-region in New Mexico, con- ducted by myself, under direction of Lieut. G. M. Wheeler, United States Engineers,’ has extended the application of the same system. The classification of Messrs. Meek and Hayden embraces five distinct epochs, all of marine deposits. The lowest is a sandstone, which rests uncon- formably on Azoic, Carboniferous, Jurassic, or other beds, as the case may be: it is succeeded by a series of usually dark-colored shales or clays, or No. 2, which is overlaid by a gray, white, or yellow chalk or calcareous matl, which forms the surface-rock of a large area; this is No. 3. The superincum- bent divisions, Nos. 4 and 5, consist of laminated shaly clays and sandy beds respectively. Above this point, the character of the deposits becomes brackish and lacustrine, constituting an approximation to the overlying Tertiary forma- tions. This physical change has been regarded by the stratigraphers as the boundary-line between the Cretaceous and Tertiary periods; and the indica- tions derived from the vegetable fossils are not inconsistent with such a view. The vertebrate paleontology, on the other hand, shows the interruption in that kind of animal life to have taken place much higher up in the series; hence, in the present work, the Lignite, or Fort Union, epoch is included in the Cretaceous formations as No. 6. ‘See Appendix F F 3 of Annual Report of the Chief of Engineers, Washington, 1874. 16 IL.—THE DAKOTA EPOCH. The sandstones of this division are light-brown, buff, or white, moder- ately soft or very hard, and varied with occasional conglomerates. They are extensively developed on the Missouri, reaching 1,500 to 2,000 feet in depth. They appear all along the eastern flank of the Rocky Mountains, and on the west side of the Sierra Madre or San Juan. No vertebrate fossils have yet been obtained from them. II.—THE BENTON EPOCH. This formation embraces dark, lead-colored shales and clays, and is found lying on the preceding in most regions where it occurs. It includes many mollusks, some of which are identical with those of No.3. Among these are Ostrea congesta and Inoceramus problematicus. Four vertebrate species have been defined from the numerous remains discovered, viz: Lamna ? cuspidata, a shark; Pelecorapis varius, an ally of the flying-fish; Apsopeliz sauriformis, a related fish ; and Hyposaurus vebbii, a gavial-like crocodile. IlJ.—THE NIOBRARA EPOCH. The exposures of this formation have a wide area between the Carbonif- erous and Lower Cretaceous beds of the east of the plains and the Rocky Mountains, and in Texas and Eastern New Mexico. Vertebrate fossils are very abundant, and I have received them from Kansas, Colorado, Texas,’ and New Mexico. The following description is from the notes of my Kansas expedition of 1871: “The geology of the regions marked by this formation is quite simple. The following description of the section along the line of the Kansas Pacific Railroad will probably apply to similar sections north and south of it. The formations referable to the Cretaceous period on this line are the Dakota, Benton, and Niobrara groups, or Nos. 1, 2, and 3. According to Leconte,” at Salina, one hundred and eighty-five miles west of the State line of Missouri, the rocks of the Dakota group constitute the bluffs, and continue to do so as far as Fort Harker, thirty-three miles farther west. They are “a coarse, 1 From this region from Dr. A. R. Roessler. 2 Notes on the Geology of the Survey for the Extension of the Union Pacific Road, Eastern Division, from the Smoky Hill to the Rio Grande. By John L. Leconte, M. D., Philadelphia, 1868. 17 brown sandstone, containing irregular concretions of oxide of iron,” and nu- merous mollusks of marine origin. Near Fort Harker, certain strata contain large quantities of the remains (leaves, chiefly) of dicotyledonous and other forms of land-vegetation. Near this point, according to the same authority, the sandstone-beds are covered with clay and limestone. These he does not identify, but portions of it from Bunker Hill, thirty-four miles west, have been identified by Dr. Hayden as belonging to the Benton, or second, group. The specimen consisted of a block of dark bluish-gray clay-rock, which bore the remains of the fish Apsopelix sauriformis, Cope. "That the eastern bound- ary of this bed is very sinuous is rendered probable by its occurrence at Brookville, eighteen miles to the eastward of Fort Harker, on the railroad. In sinking a well at this point, the same soft, bluish clay-rock was traversed; and, at a depth of about thirty feet, the skeleton of a saurian of the crocodilian order was encountered, the Hyposaurus vebbir, Cope. “The boundary-line, or first appéarance, of the beds of the Niobrara divi- sion has not been pointed out; but, at Fort Hays, seventy miles west of Fort Harker, its rocks form the bluffs and outcrops everywhere. From Fort Hays to Fort Wallace, near the western boundary of the State, one hundred and thirty-four miles beyond, the strata present a tolerably uniform appear- ance. They consist of two portions: a lower, of bluish calcareo-argillaceous character, often thin-bedded; and a superior, of yellow and whitish chalk, much more heavily-bedded. Near Fort Hays, the best section may be seen at a point eighteen miles north, on the Saline River. Here the bluffs rise to a height of two hundred feet, the yellow strata constituting the upper half. No fossils were observed in the blue bed; but some moderate-sized Os- tree, frequently broken, were not rare in the yellow. Half-way between this point and the fort, my friend N. Daniels, of Hays, guided me to a denuded tract, covered with the remains of huge shells described by Mr. Conrad, at the close of this section, under the names of Haploscapha grandis and H. eccentrica. They may have affinities to the oysters; some of them were 27 inches in diam- eter. ‘They exhibited concentric obtuse ridges on the interior side, and one species a large crest behind the hinge. Fragments of fish-vertebree of the Anogmius type were also found hereby Dr. J. H. Janeway, post-surgeon. These were exposed in the yellow bed. Several miles east of the post, Dr. Janeway pointed out to me an immense accumulation of Inoceramus proble- maticus in the blue stratum. This species also occurred in abundance in the ia) One, 18 bluffs west of the fort, which were composed of the blue bed, capped by a thinner layer of the yellow. Large globular or compound globular argillace- ous concretions coated with gypsum were abundant at this point. “Along the Smoky Hill River, thirty miles east of Fort Wallace, the south bank descends gradually, while the north bank is bluffy. This, with other indications, points to a gentle dip of the strata to the northwest. The yellow bed is thin or wanting on the north bank of the Smoky, and is not observable on the north fork of that river for twenty miles northward, or to beyond Sheridan station on the Kansas Pacific Railroad. Two isolated hills, ‘The Twin Buttes,’ at the latter point, are composed of the blue beds, here very shaly, to their summits. This is the general character of the rock along and north of the railroad between this point and Fort Wallace. “South of the river, the yellow strata are more distinctly developed. Butte Creek Valley, fifteen to eighteen miles to the south, is margined by bluffs of from twenty to one hundred and fifty feet in height on its southern side, while the northern rises gradually into the prairie. These bluffs are of yellow chalk, except from ten to forty feet of blue rock at the base, although many of the cations are excavated in the yellow rock exclusively. The bluffs of the upper portion of Butte Creek, Fox and Fossil Spring (five miles south) Cations are of yellow chalk ; and the reports of several persons stated that those of Beaver Creek, eight miles south of Fossil Spring, are exclusively of this material. Those near the mouth of Beaver Creek, on the Smoky, are of considerable height, and appear, at a distance, to be of the same yellow chalk. “J found these two strata to be about equally fossiliferous, and am unable to establish any paleontological difference between them. They pass into each other by gradations in some places, and occasionally present slight laminar alternations at their line of junction. I have specimens of Empo semianceps, Cope, from both the blue and yellow beds; and vertebree of the Platecarpus glandiferus, Cope, were found in both. The large fossil of Lzodon dyspelor, Cope, was found at the junction of the beds, and the caudal portion was excavated from the blue stratum exclusively. Portions of it were brought east in blocks of this material, and these have become yellow and yellowish on many of the exposed surfaces. The matrix adherent to all the bones has become yellow. A second incomplete specimen, undistinguishable from this species, was taken from the yellow bed. “As to mineral contents, the yellow stratum is remarkably uniform in its 19 character, The blue shale, on the contrary, frequently contains numerous concretions, and great abundance of thin layers of gypsum and crystals of the same. Near Sheridan, concretions and septaria are abundant. In some places, the latter are of great size, and, being imbedded in the stratum, have suffered denudation of their contents, and the septa, standing out, form a huge honey-comb. This region, and the neighborhood of Eagle Tail, Colorado, are noted for the beauty of their gypsum-crystals, the first abundantly found in the Cretaceous formation. These are hexagonal-radiate, each division being a pinnate or feather-shaped lamina of twin rows of crystals. The clearness of the mineral and the regular leaf and feather forms of the crystals give them much beauty. The bones of vertebrate fossils preserved in this bed are often much injured by the gvpsum-formation, which covers their surface, and often penetrates them in every direction. “The yellow bed of the Niobrara group disappears to the southwest, west, and northwest of Fort Wallace, beneath a sandy conglomerate of uncertain age. In color, it is light, sometimes white; and the component pebbles are small and mostly of white quartz. The rock weathers irregularly into holes and fissures, and the soil covering it is generally thin and poor. It is readily detached in large masses, which roll down the bluffs. No traces of life were observed in it; but it is probably the eastern margin of the southern extension of the Miocene Tertiary stratum. This is at least indicated by Dr. Hayden in his Geological Preface to Leidy’s Extinct Mammals of Dakota and Nebraska. “Economically, the beds of the Niobrara formation possess little value except when burned for use as a fertilizer. The yellow chalk is too soft in many places for large buildings, but it will answer well for those of moderate size. It is rather harder at Fort Hays, as I had occasion to observe at their quarry. That quarried at Fort Wallace does not appear to harden by ex- posure ; the walls of the hospital, noted by Leconte on his visit, remained in 1871 as soft as they were in 1867. A few worthless beds of bituminous shale were observed in Eastern Colorado. “The only traces of glacial action in the line explored were seen near Topeka. South of the town are several large, erratic masses of pink and bloody quartz, whose surfaces are so polished as to appear as though vitrified. They were transported, perhaps, from the Azoic area near Lake Superior.” The following species of Vertebrata have thus far been detected in the Niobrara formation : 20 AVES. a. SAURURA. Ichthyornis dispar. Ichthyornis celer. b. NATATORES. Graculavus anceps. Hesperornis regalis REPTILIA. a. DINOSAURIA. Hadrosaurus minor. b. ORNITHOSAURIA. Pterodactylus umbrosus, Pterodactylus ingens. Pterodactylus occidentalis. Pterodactylus velox. c. SAUROPTERYGIA. Elasmosaurus platyurus Plesiosaurus gulo. Polycotylus latipinnis. d, 'TESTUDINATA. Protostega gigas. Toxochelys latiremis. Cynocercus incisus. e. PYTHONOMORPNA. Liodon proriger. Liodon dyspelor. Liodon nepeolicus. Liodon. micromus. Platecarpus ictericus. Platecarpus corypheus. Platecarpus felix. Platecarpus curtirostris. Platecarpus crassartus. Platecarpus simus. Platecarpus latifrons. Platecarpus gracilis. Platecarpus glandiferus. Platecarpus mudget. Platecarpus tectulus. Stronectes anguliferus. Clidastes cineriarum. Clidastes pumilus. Clidastes vymanit. Clidastes velox. Clidastes dispar. Clidastes affinis. Clidastes tortor. Clidastes stenops. Clidastes planifrons. Clidastes 7 cx Mae EM DUE NO te ARN Mo sea ee TR PISCES. a. ISOSPONDYLI. Portheus molossus. Portheus thaumas. Portheus lestrio. Portheus mudgei. Portheus arcuatus. Portheus gladius. Ichthyodectes anavdes. Ichthyodectes ctenodon. Ichthyodectes hamatus. Ichthyodectes prognathus. Ichthyodectes multidentatus. Ichthyodectes perniciosus. Xiphactinus audac, Daptinus phlebotomus. Saurocephalus lanciformis. Saurocephalus arapahovius. Ervisichthe nitida. Pachyrhizodus caninus. Pachyrhizodus latimentum. Pachyrhizodus kingi. Pachyrhizodus leptopsis Pachyrhizodus sheareri. Tetheodus pephredo. Enchodus petrosus. Enchodus dolichus. Enchodus anceps. Enchodus calliodon. Enchodus shumardi. Phasganodus dirus. Phasganodus gladiolus. Phasganodus carinatus. Empo nepeolica. Empo semianceps. Empo contracta. Empo merrillit. Stratodus apicalis. b. ELASMOBRANCHI. Ptychodus janevaii. Ptychodus polygyrus. Ptychotlus occidentalis. Ptychodus mortonia. Ptychodus whippleyi. Galeocerdo crassidens. Galeocerdo hartwellit. Otodus divaricatus. Oxyrhina extenta. Lamna cuspidata. Lamna mudgei. DLamna macrorhiza... — 2.5.2 s2< 2022s o0ce eee eee Eee AS Total numiber of ispecies. . - 2... + 2222.22 23 see 59 Of the preceding forty-eight species of fishes, the greater part are phy- sostomous Actinopteri ; and there is no species of a physoclystous family in the list. No trace of spines or scales of fishes of the latter character have been yet discovered in strata of this period in the West, though one (Beryr 23 insculptus, Cope) has been discovered by Dr. Lockwood in the greensand- marl of New Jersey (No. 5). In the second place, it is of importance:to observe that the genera have nearly all been obtained from the chalk of Europe. Portheus is represented, perhaps, by some specimens referred to Hypsodon; one species of Ichthyo- dectes is figured by Dixon from Sussex, and one of Cimolichthys, Erisichthe, and Pachyrhizodus, each. Linchodus has long been known from Holland, &c., Apsopeliz and Stratodus being, so far, the only ones not found in Europe. This is of much interest in every aspect, and points to the synchronism, as generally understood, between the chalk-formations of Kansas and of England. Species of Mollusca are not numerous in the beds of the Niobrara epoch. They consist chiefly of Jnocerami of two or more species. Through the kind assistance of my friends, N. Daniels of Hays, and Dr. J. H. Janeway, post- surgeon at Fort Hays, I was enabled to procure from the yellow chalk a number of very complete specimens of the remarkable shells already men- tioned. IT submitted them to my colleague, T. A. Conrad, and add herewith his account of them. He thinks they possess some resemblance to the Ru- distes ; but he doubts their being truly related to that division. Fragments of these Haploscaphe are common in the formation, and have been described by authors as portions of huge Lnocerami. “HAPLOSCAPHA, Conrad. “Shell subovate or subtriangular; hinge long and straight, edentulous, oblique; curved, prominent ridges occupy the upper portion of the interior, the ridges beginning and ending at a distance from the margins of the shell; a singular twisted callus composes the hinge, the back of which is transversely ribbed. ‘““H. Granpis, Conrad. “Length greater than height ; hinge-line very long; ridges concentric, about twelve in number, extending into the cavity under the hinge. “This shell, Professor Cope informs me, has been found 27 inches in diameter. The posterior side of the right valve is elongated and dilated, and the form of the shell is not unlike that of Ad/eleagrina. The substance is fibrous, or rather columnar, and much resembles that of Caprinedia, as figured by @Orbigny, except that the fibers are transverse. The exterior is always 24 concealed by a coating of rock and a crowded mass of Ostrea congesta, and, in some specimens, they line the cavity of the shell; the submargin is thick. No muscular impression can be traced, unless the ridged part indicates its station. “Subgenus CUCULLIFERA. “Shell with an upright hood-shaped process on the posterior end of the hinge. ““H. eccenTRIcA, Conrad. ‘“‘ Ovato-triangular; hinge-line short, very thick; concentric ridges pro- found, six in number; hood strongly and irregularly plicated; cavity profound. “This shell, with the same structure of substance as the preceding, is very unlike it in form, and is represented by one valve only, while a number of the preceding species.were found. In all specimens of the two forms, the right valve only was obtained. Whether it is allied to the family Rudistes of Lamarck is a question I leave for others to decide. On the margin of one of the valves are attached some small shells, resembling Hippurdtes, and the fibers of which the shell is composed lie in broken masses on some valves, and even scattered like piles of pins. “The hood of H. excentricus is 24 inches in height, and the height of the valve 10 inches; length, 9 inches. ‘Accompanying these fossils were many specimens of Inoceramus pro- blematicus, and a fragment of an undetermined species of the same genus.” IV.—PIERRE GROUP. In Nebraska and Dakota and Middle Colorado, south of the divide between the waters of the Arkansas and Platte Rivers; also, the lower bed of greensand of New Jersey; Weber River, Wyoming,' below the coal. Besides the numerous remains of reptiles and fishes found in NewJersey, this formation contains saurian (mosasauroid) remains in Colorado. ‘ V.—THE FOX HILLS GROUP. Extended in Central Dakota; on the Arkansas and tributaries ; in South- ern Colorado; and as the second greensand bed in New Jersey.” 1 Hayden’s Annual Report, 1870, p. 167. * Por a synopsis of the extinct Mepfilia of this epoch and the preceding, see the author's “ Extinct Batrachia,” &c., N. America, Philadelphia, 1869~70, 25 VI—THE FORT UNION OR LIGNITE GROUP. With this epoch we enter debatable ground, and begin to consider strata deposited in brackish or fresh waters, which were more or less inclosed by the elevation of parts of the Rocky Mountains and other western regions, and which are, therefore, more interrupted in their outlines than the marine for- mations which underlie them. Dr. Hayden has recognized and located a number of formations of this character, to some of which he has applied the name of “transition-beds.’ That the period of their deposit was one of transition from marine to lacustrine conditions is evident; and that a succes- sion of conformities in position of beds may be traced from the lowest to the highest of them, and with the Tertiary strata above them at distinct locali- ties, beginning at the south and extending to the north, is also proven by Hayden and others. It appears impossible, therefore, to draw the line satis- factorily without the aid of paleontology; but here, while evidence of inter- ruption is clear, from the relations of the plants and vertebrate animals, it is not identical in the two cases, but discrepant. I therefore append a synopsis of the views expressed by authors, with a presentation of the evidence which is accessible in my department. Hayden has named the following as distinct epochs of transitional char- acter, all of which he originally referred to the Tertiary period. - I give them in the order of age which he has assigned to them:’ (1.) Placer Mountain; locality, New Mexico. (2.) Catton City coals, Southern Central Colorado. (3.) Fort Union or Lignite group, Dakota, Montana, and Wyoming. (4.) The Bitter Creek series, embracing the Bitter Creek coals, Wyoming. (5.) Bear River group, Western Wyoming. To these may be added the Judith River beds of Montana, which Dr. Hayden has placed, with reservation, below the Fort Union series, leaving their final location to future discoveries. No vertebrate remains having come under the author's notice from the Placer Mountain and Cation City formations, no further notice can be here taken of them beyond the statement that they are, as Meek indicates, of Cre- taceous age, not far removed from the horizon of the coals of Weber River, Utah. The presence of ammonites and baculites above and below them had already indicated such a conclusion to Leconte,* as it has in the case of the 1 Geological Survey of Colorado, 1869, p. 90. * Report on the Geology of the Smoky Hill Pacific Railroad route, 1868, p. 66. AC¢ 26 Weber River beds to Dr. Hayden. To near the same horizon are perhaps to be referred the coal observed by Professor Marsh*® on the south side of the Uintah Mountains in Utah, which were overlaid by strata containing Ostrea congesta. ‘This may, indeed, be referred to a still older period, as that oyster is characteristic of No. 3, according to Meek and Hayden. The Placer Mountain and Canon City groups are nearer to No. 5, but the precise relation to it has not yet been determined. I therefore proceed to the proper and original Fort Union epoch as defined by Hayden. This extended deposit is stated by Hayden® to extend from the Missouri Valley to Colorado, passing under Tertiary beds by the way. That this is the case has been confirmed by the researches conducted in the northern and eastern portions of Colorado during the season of 1873 by the writer.* I present comparative lists of the vertebrate species known from the Platte and Missouri Valleys in the respective Territories. COLORADO. DAKOTA. Compsenvys victus. Compsemys victus. Adocus lineolatus. Adocus lineolatus. Plastomenus punctulatus. Plastomenus punctulatus. Plasotmenus insignis. sa = # % Trionyx vagans. Trionyx vagans. * z a 3 Ischyrosaurus antiquus. 53 * * r Plesiosaurus occiduus. Bottosaurus perrigosus. 3 2 ; i Polyonax mortuarius. 4 * ‘ @ Cionodon arctatus. ¢ 53 3 2 Hadrosaurus ? occidentalis. Hadrosaurus occidentalis. The identity and correspondence of the species in the two columns indi- cate that these remote localities contain the remains of the same fauna. Further, the presence of Dinosauria and Sauropterygia demonstrates its mesozoic character. A number of vertebrate remains was collected by George W. Dawson, ‘Annnal Report, 1870, p. 168. >See an interesting article by Prof. O. C. Marsh on the Geology of the Eastern Uintah Mountains in the American Journal of Science and Arts for March, 1871. *Annual Report Colorado, 1869, p. 89. +See Balletin of the United States Geological Survey, No. 1, 1874, p. 10. 27 of Montreal, geologist of the British American Boundary Commission, near the line of the northern boundary of the United States (latitude 49°), within the drainage-area of the Milk River. The formations are regarded by him as belonging to the Lignite or Fort Union of Dr. Hayden, and consist of green- ish and greenish-brown arenaceous clays of various degrees of hardness, fre- quently including small gravel-stones, and sometimes forming a hard cement between them. The fossils were found near the base of the formation, and “not more than one or two hundred feet above yellow arenaceous beds, which I conceive represent Cretaceous No. 5, and which are rapidly followed in descending by well-marked No. 4 with characteristic fossils.” (Extracted from letter of Mr. Dawson.) The species are the following: Clastes, sp.; Compsemys ogmius; C. ? victus; Plastomenus costatus;* P. coalescens; Trionyx ?vagans; Trionyx ?sp.; ? Hadro- saurus ?sp.; Cionodon stenopsis. The dinosaurian remains are quite abundant, and indicate several species, but are mostly so fragmentary as to be unfit for determination. The diagnos- tic genera of this list are Compsemys, Plastomenus, and Cionodon; the species referred to Hadrosaurus being represented by caudal vertebre only. The first-named genus is characteristic of the Fort Union epoch only; the frag- ment referred to C. victus, the only species of the list previously known, is too small for final specific reference. The Plastomenus coalescens is represented by amore perfect specimen than any other species referred to this genus from the Fort Union beds, but is not sufficiently complete to render the reference to this Eocene genus final. It is, in any case, not a member of any other known genus. One species of Trionyx is represented by a hyosternal bone, and is not definable; while the fragment referred to 7. vagans, though closely reseinbling that species, is not large enough for final determination. The Cronodon, though based on incomplete remains, is quite suflicient for paleon- tological purposes. In conclusion, it may be stated that there are present two genera in this collection which are diagnostic of the Fort Union epoch, but no species cer- tainly so, though two species are probably identical with species of that epoch; also, that the presence of Dinosauria refers the fauna to the Mesozoic series; and that there is no satisfactory evidence of the co-existence of these reptiles 1 Two species are provisionally referred to the Tertiary genus Plastomenus, but are too fragmentary for final determination. 28 with Tertiary forms; that the species referred to Plastomenus constitute an indication of affinity with corresponding Eocene forms. The presence of gar-_ fishes of the genus Clastes in this formation is as yet peculiar to this and the Judith River localities. As these gars have not heretofore been found in North America below the Eocene, they constitute the first case of apparent commingling of Tertiary and Cretaceous animal life yet clearly determined. Yet the evidence is far from being as weighty in indication of Tertiary rela- tions as is the presence of the saurians in question as evidence of Mesozoic character; for the gars, though now living, are an ancient type, their allies having swarmed in the Jurassic seas, and it is therefore altogether reason- able that they should be found in fresh-water deposits of Cretaceous and Tertiary age. The rarity of the former deposits accounts for the late date of their discovery there. The longest known of these transitional faunze was discovered by Dr. Hayden near the mouth of Judith River, in Montana. As determined by Dr. Leidy, it embraces the following Vertebrata: Hadrosaurus mirabilis ; Paleos- cincus costatus; Troédon formosus ; Aublysodon horridus; Bottosaurus? humilis ; Trionyx foveatus ; Clastes occidentalis (Lepidotus, Leidy) ; Lepidotus haydenii. The first four species of this list are Dinosauria, and hence diagnostic of the Mesozoic age of the formation. The Clastes indicates relation to the Milk River fauna. That the Judith River formation is Cretaceous would appear to have been the suspicion of Messrs. Meek and Hayden when they originally described the deposit and its invertebrate fossils. Leidy suspected that the species “indicate the existence of a formation like that of the Wealden in Europe.”* Meek and Hayden* remark: “We are inclined to think with Professor Leidy that there may be, at the base of the Cretaceous system, a fresh-water formation like the Wealden. Inasmuch, however, as there are some outliers of fresh-water Tertiary in these lowlands, we would suggest that it is barely possible these remains may belong to that epoch.” From the standpoint of the writer, these beds would be at the top of the Cretaceous, and more or less related to the Fort Union epoch. Mr. Meek expresses himself* cautiously with refer- ence to the age of the Fort Union and Judith River formations, as follows: ‘Proceedings of the Academy of Natural Sciences, Philadelphia, 1856, p. 73. 2. c., 185G, p. 114. Hlayden’s Anoual Report for 1872, p. 460. 29 “The occurrence of [fossils specified] at the Judith River localities would certainly strongly favor the conclusion, not only that this Judith formation, the age of which has so long been in doubt, is also Cretaceous, but that even the higher fresh-water Lignite formation at Fort Clark and other Upper Mis- souri localities may also be Upper Cretaceous instead of Lower Tertiary. That the Judith River beds may be Cretaceous I am, in the light of all now known of this region of the continent, rather inclined to believe. But it would take very strong evidence to convince me that the higher fresh-water Lignite series of the Upper Missouri is more ancient than the Lower Eocene. That they are not is certainly strongly indicated not only by the modern affinities of their molluscan remains, but also by the state of preservation of the latter.” | I presume it is now apparent that the presence of the orders Sawropte- rygia and Dinosauria establishes, conclusively, the Mesozoic and Cretaceous character of this fauna. This reference was made by the writer in 1869, and was, at that time, opposed to the views extant, both geological and _pale- ontological. The following list exhibits the state of opinion on this point at that time and subsequently. 1856. Meek and Hayden, Proceedings of the Academy, Eladelphie p. 63; referred them to the Tertiary. Meek and Hayden, /. c., p. 265; Lignite, ieceae to the Miocene. Meek and Hayden, /. c., 113; referred to Lower Tertiary. Leidy, Zc. p. 312; Thespesius oocidentalis (Hadrosaurus) ; referred to the Mammalia, and regarded as dinosaurian. Leidy, 7 c., p. 89; Ischyrosaurus referred to the Mammalia as a sirenian. | 1860. Hayden, Transactions of the American Philosophical Society, p. 123; repeats former conclusions; Leidy refers Thespesius more decidedly to the Sauria, and questions relations of Ischyrosaurus. 1868. Hayden, American Journal of Science and Arts, p. 204; Lignites regarded as Tertiary, from both vegetable and animal remains, from the Missouri and the Laramie Plains. Leconte, Exploration of the Smoky Hill Railroad Route, p. 65; the Middle Colorado beds are “older than those of the Missouri or Great Lignite bed of Hayden, which are probably Miocene,” &e. 30 1869. Cope, Transactions of the American Philosophical Society, pp. 40, 98, 243; supposed mammalian remains proven to be reptilian, and the formation referred to the Cretaceous. 1871. Newberry, in Hayden’s Annual Report, pp. 95-96; Lignite flora regarded as Miocene. 1874. Dawson, Report of Progress of the British North American Boundary, Commission: on the Tertiary Lignite Formation, p. 20; Milk River beds regarded as lowest American Tertiary. Cope, Bulletin of the United States Geological Survey of the Territo- ries, No. 2 (April); Fort Union beds of Colorado referred to the Cretaceous. ¢ 1875. Cope, Proceedings of the Academy of Natural Sciences, Philadelphia (January); Milk River beds regarded as Cretaceous. From the above, it appears that both paleontologists and stratigraphers, excepting the writer, have maintained the Tertiary age of the beds of the Fort Union epoch. Whether the Bitter Creek and Bear River groups of Hayden present much difference of horizon remains to be determined. For the present, they are retained as distinct. VII.—THE BITTER CREEK SERIES, mentioned by the writer as a distinct group, in the Proceedings of the Amer- ican Philosophical Society, 1872 (published on August 12), is apparently regarded by Mr. Meek also as representing a distinct epoch. He says, “The invertebrate fossils yet known from this formation are, in their specific rela- tions, with possibly two or three exceptions, new to science, and different from those yet found either at Bear River, Coalville, or indeed elsewhere in any established horizon, so that we can scarcely more than conjecture, from their specific affinities to known forms, as to the probable age of the rocks in which we find them.” On this account, and because of the great stratigraph- ical differences exhibited by the Bear River and Evanston coal-strata, I have followed Hayden in regarding the Bear River group, on the west side of the Bridger basin, as representing a distinct series of rocks, with present knowl- edge. On this account I omit, as heretofore, allusion to determinations ' Hayden’s Annual Report for 1872, pp. 459-461; published April, 1873. dl of age of the latter formation as irrelevant in discussing the age of the Bitter Creek epoch.’ My own observations on the relations of these rocks, made during the summer of 1872, have been, in a measure, anticipated by the detailed reports of Messrs. Meek and Bannister,” which, with the older observations of Dr. Hayden and Mr. Emmons (of King’s survey), leave little to be added. How- ever, as none of these gentlemen paid especial attention to the vertebrate paleontology, the bearing of this department in relation to the stratigraphy remains to be explained. . As Dr. Hayden remarks, the Union Pacific Railroad, at Black Butte station, passes through a monoclinal valley ; the rocks on both sides having a | gentle dip to the southeast. This dip continues to the eastward to near Creston, where the beds pass under the newer Tertiary strata. Following the railroad westward from Black Butte, the same dip continues to near Salt Wells, where we cross an anticlinal axis, the dip of the strata being gentle to the northwest. There are minor variations in the dip, but the general result is as stated. They disappear five miles east of Rock Spring station, beneath the later beds of the Green River Tertiary, which, at this point, presents a line of strike extending northeast and southwest, across the railroad, in the form of a range of bluffs, of considerable elevation. They are composed of hghter-colored and softer material than the Bitter Creek strata. The latter consist of alternating beds of hard and soft sandstone, with argillaceous and carbonaceous strata. ‘The upper part of the series contains eleven coal-strata. At Rock Spring, I was informed that the upper was ten feet in thickness, and the next, four feet. Returning eastward, the heavier-bedded sandstone is low in the series at Point of Rocks, in consequence of the southeast dip, and the upper beds are softer and abound in fossil shells. At Black Butte station, the heavy sandstone-bed disappears from view toward the east, and the eleven coal-strata appear above it. About twenty feet above the sandstone, between two of the thinner beds of coal, the bones of the Agathaumas sylvestris were found, imbedded in leaves and sticks of dicotyledonous plants, cemented together by sand and clay. Where the heavy sandstone-bed disappears below the level of the track of the railroad, in the course of its eastern dip, a thin ' This course has been misunderstood by Mr. Meek and others as implying a design to ignore those determinations. Both Mr. Emmons and Mr. Meek are clear in the expression of their conclusions as to the age of the Bear River epoch. 2 2Seo Hayden’s Annual Report for 1872, pp. 457, 525. 32 bed of coal, just above it, soon follows; then a bed of shells containing oys- ters, more and less numerous at different points, may be traced for some distance before it also disappears. Near the Jatter point, a bed of Melanians and other fresh-water shells is seen a few feet above them. A section, carried for eight miles south of Black Butte station, exhibits the relation of the Bitter Creek series to the superincumbent Tertiaries very instructively. The whole series rise slightly to the southward, and more dis- tinctly to the westward, so as to form an escarpment as the eastern border of an open valley, which extends south from the railroad, just west of the station. The heavy bed of sand-rock is here, as elsewhere, the landmark and strati- graphical base-line. Moving south from the railroad, we keep along the strike of the lower coal-beds. Just above the sand-rock, the softer stratum thickens, and six miles from the station is covered with the débris of immense numbers of Leptesthes crassatelliformis. Passing over the edges of the strata, toward the southeast, I counted eight beds of coal, separated by various short inter- vals, the eighth being the heaviest, and five or six feet thick. Above this one, three thin beds of lignite were crossed in succession, each accompanied with an abundance of leaves of chiefly dicotyledonous plants. Then came the ninth bed of coal, and then, in order, three more beds of lignite, with abun- dant leaves. During this time the ascent became less steep, and a number of short, level tracts were passed before reaching the upper bed of lignite. Beyond this, I passed another short flat, which was marked by a number of worn banks of the light-ash color that distinguishes the material of the bluffs of the Green River Tertiary which overlie the coal-series near Rock Springs. J had not ridden a quarter of a mile before reaching a low line, from which one of my men picked up a jaw of a small mammalian, allied to the Bridger Hyopsodus or to Hyracotherium of the Eocene of France and Switzerland, and a number of Paludina-like shells. I had thus reached the summit of the Bitter Creek formation, which did not appear to be much more than 350 feet above its base at the railroad. In full view, a mile or two to the south, rose the first of the benches which constitute the horizons of the Green River formation. Between this and the first mammal-producing bed, just described, rose three banks, one beyond the other, measuring, altogether, 120 feet; perhaps the lowest was 10 feet above the first bank, and this one not more elevated above the last lignite and leaf-bed. In all of these I found bones of Green River Vertebra/a exceedingly abundant, but all dislocated and scattered, so as oD (979) to be rarely in juxtaposition. These consisted of the following species : Fishes: Olastes ? glaber; Reptiles: Emys megaulax ; E. pachylomus ; LE. eu- thnetus; Trionyx scutumantiquum ; Alligator heterodon; Mammals: Orohippus vasacciensis ; and fragments too imperfect for determination. In the third bank, in immediate juxtaposition with the remains just enumerated, I found another thin bed of lignite, but this time without any visible leaves. In a fourth line of low bluffs, a little beyond, I found that remarkable mammal, Metalophodon armatus, with its dentition nearly complete, in connection with fragments of other mammals and reptiles. Behind these rises the first line of white bluffs already described, which extend away to the east; to the west, they soon terminate in a high escarp- ment in north and south line with that of the Bitter Creek beds, already men- tioned as bounding a north and south valley.. This and the superjacent strata which we pass over in going south appear to be conformable to those of the Bitter Creek series beneath them. I say “appear,” for slight differences of dip are not readily measured by the eye; yet I suspect that the conformability is very close, if not exact, and similar to that mentioned by Meek and Bannis- ter as exhibited by the beds of the Washakie group which he upon the coal- series east of Creston. ‘The white bluffs add perhaps one hundred feet to the elevation. On their summit is a thin bed of buff clay and sand-rock sim- ilar to the upper strata of the Bitter Creek series, and containing numerous shells and some scattered teeth and scales of fishes. I called Mr. Meek’s attention to the specimens of these shells, which I sent him, and his reply was that most were of identical species with those of the coal-series (Creta- ceous), and that they presented no general peculiarity. At a short distance to the southward, another line of white bluffs extends across the line of travel. This is not more elevated than the preceding one. I only found remains of tortoises on it. Several miles to the south we reach another bench, whose bluffy face rises four or five hundred feet in buttress- like masses, interrupted at regular intervals by narrow terraces. This line is distinguished for its brilliantly-colored strata extending in horizontal bands along the escarpment. They are brilliant cherry-red, white, true purple with a bloom shade, yellow, and pea-green, forming one of the most beautiful dis- plays I ever beheld. The lower portions are bright-red, which color predom- inates toward the west, where the bluffs descend to a lower elevation. 1 found on them remains of a turtle (Lmys euthnetus, Cope) and some borings F o (0) 34 of a ? worm in a hard layer. On top of these are clay and slate rocks of a muddy-yellow color, with their various ledges rising to perhaps two hundred feet. Continuing now to the southeastward, along the old stage-road, we cross South Bitter Creek at the old Laclede station. Some miles south and east of this point, a band of buff sandstones form a bluff of fifty or more feet in elevation. Below it lie more white or ashen beds, which contain remains of mammals and turtles, rather decayed. A short distance beyond these, and forty miles from Black Butte station, we reach the base of the enormous pile of sediment which I have called the Mammoth Buttes. These form a horse- shoe-shaped mass, the concavity presenting south and eastwardly, the summit narrow, serrate, and most elevated to the east, and descending and widening toward the south. I estimated the height of the eastern end to be at least one thousand feet above the plain surrounding it. Numerous mammalian remains? demonstrated that this mass is a part of the Bridger Eocene; although, as Mr. Emmons, of King’s survey, informs me, no continuous connection with the principal area west of Green River can be traced. The total thickness of the Green River and Bridger formations on this section cannot be far from two thousand five hundred feet, at a very rough estimate. - The point of transition from the Cretaceous to the Tertiary deposits, as indicated by the vertebrate remains, is then in the interval between the last plant-bed at the summit of the buff mud-rocks and the mammal-bone deposit in the lowest of the ash-gray beds. Below this line, the formation must be accounted as Cretaceous, on account of the presence of the dinosaurian Aga- thaumas sylvestris, and those above it, as I have already pointed out, Eocene,” on account of the types of J/ammalia contained in them. The authorities on the Bitter Creek formation have presented views more or less at variance with those entertained by the writer, or of such a dubious character as to fall very far short of the requirements of evidence. Dr. Hayden has regarded them as Tertiary and as transitional from Creta- ceous to Tertiary. Mr. King, in his very fall article on the Greon River Basin, definitely refers the lower part of the series to the Cretaceous, in the follow- ing language:* ‘‘ We have then here the uppermost members of the Cretaceous series laid down in the period of the oceanic sway, and quite freely charged ‘See the Monster of Mammoth Buttes, Penn Monthly Magazine for August, 1873. 2 On Bathmodon, an extinct genus of Ungulates, February 16, 1872, Hayden’s Annual Report (1872), p. 431; Annual Report for 1872, p. 645. % Exploration of the Fortieth Parallel, p. 458. 30 with the fossil relics of marine life; then an uninterrupted passage of con- formable beds through the brackish period up, till the whole Green River basin became a single sheet of fresh water.” He regards the line of the upper bed of oysters as the summit of the Cretaceous, and the superimposed beds as Tertiary, in the following language (page 453): ‘while the fresh- water species which are found in connection with the uppermost coal-beds seem to belong to the early Tertiary period.” He thus places the line some distance within what I have regarded as the Cretaceous boundary. Mr. Lesquereux, as is known, regards these beds as Tertiary, not only on account of their vegetable fossils, but also on account of the stratigraphic relations of the formation. His conclusion to this effect is consistent through- out, and is a fact of the highest importance in this connection. Mr. Meek has fully discussed the age of this series in his interesting article in Hayden’s Annual Report for 1872, the general tenor of which is indicated by the passage I have quoted from the opening of his remarks, in the beginning of the present notice of the Bitter Creek beds. His opinions may be cited as follows: In the Annual Report for 1870, he determined the same beds visible at Hallville as Tertiary; in that of 1871, three species of oysters from other parts of the Bitter Creek beds are placed in the Cretaceous list, each one with question as to the identification of species, a point, in the case of oysters, of first importance in the determination of the age of the deposit. The remarks in this report, as well as those in Mr. King’s report. refer either to the much lower Weber River coal or to the different area of the Bear River group, and are consequently noticed under that head. In a paper on the age of these beds, published August 12, 1872, the writer asserted the Cretaceous age of the series. On this, Dr. Bannister, the com- panion of Mr. Meek, writes’ “that Mr. Meek, and, I believe, Mr. Emmons also, had considered that these beds might be Cretaceous; but this was rather on account of the change in the fossil fauna from purely fresh-water, as in the characteristic Tertiary of this region, to brackish-water marine, and the spec- ific affinities of a few of the fossils to California Cretaceous species, than from any very positive evidence. As far as I know, the only evidence of this kind is in the identification by Professor Cope of the saurian remains found by us at Black Butte.” It only remains to observe that the strata and coal of the Bitter Creek 1 Annual Report for 1872, p. 524. 36 group of the Cretaceous are either wanting on the western and southern borders of the Green River basin, or are concealed by the superincumbent Tertiaries. Instead of these, a comparatively thin bed of apparently unfos- siliferous quartzite or sandstone lies at a high angle against the bases of the Uintah* and Ham’s Fork Mountains, respectively, on beds of Jurassic age, which are probably Cretaceous No. 1 (Dakota). The beds observed by Pro- fessor Marsh, on the south side of the Uintah Mountains, on Brush Creek, belong neither to the Dakota nor Bitter Creek epochs, but perhaps to No. 3, if, as Professor Marsh asserts, the oyster found in a superjacent stratum is Ostrea congesta, Con. It is, in any case, of no later date than the Canyon City or Weber River coals. Hence, the assumption of some writers that this dis- covery determined the age of the Bitter Creek series to be Cretaceous is without foundation in fact. VIII.—THE BEAR RIVER GROUP, of Hayden, occupies, according to him, a distinct basin, to the west of an anticlinal axis, which separates it from that of Green River. It is buried under Tertiary beds, the age of which has been a question of interest, and will be hereafter considered. In order to determine the relations of the two basins, a section was carried across the rim of the eastern, starting from the Fontanelle Creek, eighty miles north of the Union Pacific Railroad, and con- tinuing toward the upper waters of Ham’s Fork of Green River to the westward. My notes are as follows: The beds of the Green River epoch dip gently from the point where my last notes left them, near to Rock Spring station, toward the northwest, all the way to Green River. The upper strata become slaty in character, and descend to the water-level at the river, where they form a high bluff. In these slates occur the fish-beds discovered by Dr. Hayden, as well as the insect-beds noticed by Messrs. Denton and Richardson. They are worn into towers and other picturesque forms at Green River City (see Hayden’s Annual Report for 1870). Passing north from the railroad, up the valley of Green River, the slates display a gentle dip to the north, and eighteen miles beyond haye disappeared from view. On both sides of the river huge mesas of the Bridger formation come into view; those on the east extending to the 1See Hayden’s Annual Report for 1870; Marsh, American Journal of Science and Arts, March, 1871. oF Big Sandy River, and those on the west to Ham’s Fork. At Slate Creek, further to the north twenty miles, a yellowish-brown sandstone rises into view, and continues to increase in importance toward the north. At the mouth of Fontanelle Creek, it rises on the east side of the river to a heigh’ of perhaps 250 feet, but sinks toward the north and east, from near the mouth of La- barge Creek, fifteen miles up the river. North of Labarge, a similar bed of sandstone rises again, and is immediately overlaid by white shales, resembling those of the Green River epoch, which have here a great thickness. Oppo- site the mouth of the Labarge, their lower strata are bright-red; but, on the west side of the river, the sandstone only is visible. All the beds rise to the north ; the red beds forming the summits of the cliffs in that direction. In passing up Fontanelle Creek to the westward, the heavy beds of buff sandstone gradually descend, and the white shales come into view. I exam- ined the former for lignite and coal, but found none. There are several thin beds of a tough, carbonaceous material in the white shales (which I take to be of the Green River epoch). In the lower strata in this locality, as well as on the east side of Green River above the mouth of Labarge Creek, are nu- merous remains of fishes similar to those of Green River City, with insects and their larvee, shells like Pupa and Cyrena, and millions of Cypris. The larvee are dipterous, some nearly an inch long, and others minute and in pro- digious numbers. With them are found stems of plants, but no leaves. These beds rise witha very gentle dip, and, twenty miles from the mouth of the creek, terminate against stecply-inclined strata of earlier age. At this point the lower beds exhibit the bright-red colors that are so often seen in the lower part of the formation at other points. The uplifted beds form a ridge of high hills, having a nortb by east and south by west trend, across which the Fontanelle cuts its way in a deep cafion. This range is monoclinal; the strata dipping 45° east, and their outcrop on the summit and western face. The first bed which forms the surface of the incline is rather thin, and is composed of a reddish quartzite without fossils, no doubt of Cretaceous age. Below it is a stratum of highly fossiliferous bluish limestone of Jurassic age, containing Pentacrinus asteriscus, M. and H.; Trigonia, &c. Below this, a reddish sandstone presented a similar thickness, which may represent the Trias, which rests on a bluish-shale formation. We have now reached the ~ base of the western side of the hills; from their summit, we have had a beau- tiful and interesting view of geological structure. The valley, of three or four 38 miles in width, is bounded on the west side by a range of low mountains, whose summits are well-timbered. The valley is excavated at an acute angle to the strike of the strata, so that, as far as the eye can reach to north and south, successive hog-backs issue, en. échelon, from the western side, and run diagonally, striking the eastern side many miles to the southward. At the canon of the Fontanelle, six of these hog-backs occupy the valley, and the number varies as we proceed down the valley. The structure changes from the same cause, as we explore in either diggction. The dip of all these hog- back strata is, to the west and slightly north, less steep at the eastern side, but reaching 45°, and a still higher angle at the middle and west side of the valley. There appears to be an anticlinal near the base of the eastern range, which has been deeply excavated; from its western slope (in the valley), the upper beds, seen in the eastern range, have been carried away, leaving only probable Triassic and Carboniferous strata exposed. In one of the latter, I found a well-marked horizon of carbonaceous shales, extending as far as I explored them. Toward the western side of the valley, the descending ‘strata are sandstones, but, whether identical with that of the eastern hills of Creta- ceous age, I could not ascertain. Lower down the valley (to the- south), similar beds form a high, vertical wall of very light color, the scenery resem- bling that of the Garden of the Gods in Colorado. I suspect that the exist- ence of more than one fold can be demonstrated in these hog-backs and mountains. The result, which bears on the history of the Bear River group, is, that, on this side of the Green River basin, the Bitter Creek epoch is either want- ing, or represented by a thin layer of red quartzite (or, perhaps, Cretaceous No. 1), and that no coal of Cretaceous age exists along its western rim. After following the valley to Ham’s Fork River, and proceeding a short dis- tance along it, toward the southeast, I crossed a thin bed of coal in the upturned edges of the same beds crossed in the valley above. The discovery of the extension of the fish and insect beds sixty miles north of the principal localities is a point of interest in Tertiary geology. The Ham’s Fork Mountains form the divide between the waters of Green and Bear Rivers, respectively, and is passed by the Union Pacific Railroad at and west of Aspen station, as is described by Dr. Hayden (Annual Report for 1870, p.149). He here points out that the distinctness of the two basins was marked during the Tertiary period. and hence names the deposits of the 39 western area the Wahsatch group, regarding it, at the same time, as synchro- nous with those of the Green River epoch. The writer has attained the same opinion on paleontological grounds, and has hence employed the same name for both areas, viz, the Green River-epoch.' As already stated, the upper or red-banded Tertiary beds of this locality yielded the following species: Pertssodaetyle bones, two species ; Orohippus vasacciensis ; Crocodilus, sp.; Alligator heterodon ; Trionyx scutumantiquum ; Emys testudineus ; E. gravis ; Clastes glaber ; Unio, two species. The lower sandstone-beds yielded the following mammals: Bathinodon radians; B. semicinctus; B. latipes; Orohippus index 3° _Phenacodus primevus. West of the contact of Bear River with tne Tertiary bluffs, the strata consist of sandstone and conglomerates, and dip at about 36° to the northeast. Five hundred feet vertically below the Bathmodon bed, a stratum of impure limestone crops out, forming the slope and apex of a portion of the bluff. In this I found the following vertebrates: Reptiles: Trionyx scutumantiquum ; Emys ? euthnetus; Fishes: Rhineastes calvus ; Clastes glaber. In comparing this list with that given for the lower beds of the Green River epoch, where they overlie the Bitter Creek coal, such resemblance may be observed as is sufficient to identify the two series. This is the nearest to a determination of the age of the Evanston coal- bed, which Hayden regards as the most important west of the Missouri River that I have been able to reach. From the limestone just described to the coal-bed two miles to the west, the strata are very similar in character, and apparently conformable, so that they appear to belong to the same series. Dr. Hayden confesses his inability to correlate them with those of Bear River City and Weber River, but discovered remains of plants which were identi- fied with some of those known to occur in the Fort Union beds on the Lara- mie Plains and the Upper Missouri If this be the case to a sufficient extent, the Evanston coal must be referred to that division of the Cretaceous period. This conelusion is, however, only provisional, and Dr. Bannister’s remarks‘ are much to the point. He says, of the upper beds northeast of Evanston (the ones J. describe above): “There seems to have been a consider- able disturbance besides the mere tilting of the beds; and, from the altered 1 Proceedings of the Academy of Natural Sciences, 1872, p. 279. 2 Proceedings of the American Philosophical Society, 1872, p. 473. * Cope, Paleontological Bulletin, No. 17, 1873; also, The Extinct Vertebrata of New Mexico. 4Hayden’s Annual Report for 1872, p. 541. 40 direction of the strike,t we were led to suspect considerable lateral displace- ment with faulting, which might very possibly cause the appearance of the same beds both here and at the coal-mines, although at first sight these would appear much higher in geological position. $ I do not know the grounds of Professor Cope’s reference of the coal at this point to the Creta- ceous, while he admits the Tertiary age at least of some of the overlying sandstones; but, as we found no break nor line of demarkation in the whole 2,000 feet or more which we examined, and found our fossils in coal-bearing beds immediately above and conformable to the main coal, the facts, so far as they are known to me, do not seem sufficient for such identification.” This point offers, therefore, a more complete continuity in stratification and min- eral character, from the Cretaceous to Tertiary deposits, than any other which Ihave had the opportunity of examining. CONCLUSION. Having traced the transition series of the coal-bearing formations of the Rocky Mountain region from the lowest marine to the highest fresh-water epochs, it remains to indicate conclusions. I have alluded but cursorily to the opinions of Mr. Lesquereux and Dr. Newberry as based upon the study of the extinct flora. The former has, as is well known, pronounced this whole series of formations to be of Tertiary age, and some of the beds as high as Miocene. The material on which this determination is based is abundant, and it must be accepted as demonstrated beyond all doubt. I regard the evidence derived from the mollusks in the lower beds and the vertebrates in the higher as equally conclusive that the beds are of Cretaceous age. There is, then, no alternative but to accept the result ‘hat a Tertiary flora was contemporaneous with a Cretaceous fauna,* establishing an uninterrupted succes- ston of life across what is generally regarded as one of the greatest breaks in geologic time. The appearance of mammalia and sudden disappearance of the large mesozoic types of reptiles may be regarded as evidence of migration and not of creation.2 It is to be remembered that the smaller types of lizards and tortoises continue, like the crocodiles, from Mesozoic to Tertiary time 1 Hayden’s Annual Report for 1872, p. 541. 2 The circumstance of the discovery of a Mesozoic Dinosaur, Agathaumas sylvestris, with the cavities of, and between, his bones stuffed full of leaves of Eocene plants (Lesquerenx), would prove this proposi- tion to be true, had no other fossils of either kind ever been discovered elsewhere! * Griticism of this conclusion by Professor Dawson is noticed in the Report U.S. Geol. Surv. Terrs. 1873 ,p. 444. 41 without extraordinary modification of structure. It is the Dinosauria which disappeared from the land, driven out or killed by the more active and intel- ligent mammal. Herbivorous reptiles like Agathaumas and Cionodon would have little chance of successful competition with beasts like the well-armed Bathmodon and Metalophodon. It then appears that the Transition series of Hayden is such not only in name but in fact, and that paleontelogy confirms in a highly satisfactory manner his conclusion, ‘“‘already shown many times, that there is no real physical break in the deposition of the sediments between the well-marked Cretaceous and Tertiary groups.” a 1 Annual Report 1870, p. 166. Also Geol. Survey Colorado, 1869, p. 197, Dr. Hayden observes: “ There is no proof, so far as.I have observed, in all the western country of true non-conformity between the Cretaceous and Lower Tertiary beds, and no evidence of any change in sediments or any catastro- phe sufficient to account for the sudden and apparently complete destruction of organic life at the close of the Cretaceous period.” 60 Je Jelay ih Ib IE. DESCRIPTIONS OF VERTEBRATE FOSSILS. DESCRIPTION OF THE FOSSILIFEROUS LOCALITIES AND ANCIENT LIFE OF KANSAS. _ The vast level tract of our territory occupied by the Niobrara Cretace- ous, and lying between Missouri and the Rocky Mountains, represents a con- dition of the earth’s surface which has preceded, in most instances, the mount- ainous or hilly type so prevalent elsewhere; and may be called, in so far, in- completely developed. It does not present the variety of conditions, either of surface for the support of a very varied life, or of opportunities for access to its interior treasures, so beneficial to a high civilization. It is, in fact, the old bed of seas and lakes, which has been so gradually elevated as to have suffered little disturbance. Consistently with its level surface, its soils have not been carried away by rain and flood, but rather cover it with a deep and wide-spread mantle. This is the great source of its wealth in nature’s crea- tions of vegetable and animal life, and from it will be drawn the wealth of its future inhabitants. On this account, its products have a character of uni- - formity ; but, viewed from the standpoint of the political philosopher, so long as peace and steam bind the natural sections of our country together, so long will the plains be one important element in a varied economy of continental extent. But they are not entirely uninterrupted. The natural drainage has worn channels, and the streams flow below the general level. The ancient ‘sea and lake deposits have neither been pressed into very hard rock beneath piles of later sediment, nor have they been roasted and crystallized by internal heat. Although limestone-rock, they easily yield to the action ef water; and so the side-drainage into the creeks and rivers has removed their high banks to from many rods to many miles from their original positions. In many cases, these banks or bluffs have retained their original steepness, and have increased in elevation as the breaking-down of the rock encroached on higher land. In other cases, the rain-channels have cut in without removing the intervening rocks at once, and formed deep gorges or caiions, which sometimes extend to 43 great distances. They frequently communicate in every direction, forming curious labyrinths; and, when the intervening masses are cut away at various levels, or left standing, like monuments, we have the characteristic peculiari- ties of “bad lands,” or mauvaises terres. In portions of Kansas, tracts of this kind are scattered over the country along the margins of the river and creek valleys and ravines. The upper stratum of the rock is a yellow chalk, the lower bluish, and the brilliancy of the color increases the picturesque effect. From elevated points, the plains appear to be dotted with ruined villages and towns whose avenues are lined with painted walls of fortifications, churches, and towers, while side-alleys pass beneath natural bridges or expand into small pockets and caverns, smoothed by the action of the wind carrying hard mineral particles. But this is the least interesting of the peculiarities presented by these rocks. On the level surfaces, denuded of soil, lie huge oyster-like shells, some opened and others with both valves together, like remnants of a half-finished meal of sone titanic race, who had been frightened from the board never to return. These shells are not as much thickened as many fossil oysters, but contained an animal which would have served as a meal for a large party of men. One of them measured twenty-six inches across. If the explorer searches the bottoms of the rain-washes and ravines, he will doubtless come upon the fragment of a tooth or jaw, and will generally find a line of such pieces leading to an elevated position on the bank or bluff where lies the skeleton of some monster of the ancient sea. He may find the vertebral column running far into the limestone that locks him in his last prison ; or a paddle extended on the slope, as though entreating aid; or a pair of jaws lined with horrid teeth, which grin despair on enemies they are help- less to resist; or he may find a conic mound, on whose apex glisten in the sun the bleached bones of one whose last office has been to preserve from destruc- tion the friendly soil on which he reposed. Sometimes a pile of huge remains will be discovered, which the dissolution of the rock has deposited on the lower level; the force of rain and wash having been insufficient to carry them away. But the reader inquires, What is the nature of these creatures thus left stranded a thousand miles from either ocean? How came they in the lime- stones of Kansas, and were they denizens of land or sea? It may be replied that our knowledge of this chapter of ancient history is only about five years 44 old, and has been brought to light by geological explorations set on foot by Dr. Turner, Professor Mudge, Professor Marsh, W. E. Webb, and the writer. Careful examinations of the remains discovered show that they are nearly all to be referred to the reptiles and fishes. We find that they lived in the period called Cretaceous, at the time when the chalk of England and the greensand- marl of New Jersey were being deposited, and when many other huge rep- tiles and fishes peopled both sea and land in those quarters of the globe. The thirty-seven species of reptiles found in Kansas up to the present time varied from ten to eighty feet in length, and represented six orders, the same that occur in the other regions mentioned. One only of the number was terres- trial in their habits, and four were fliers; the remainder were inhabitants of the salt ocean. When they swam over what are now the plains, the coast- ‘line extended from Arkansas to near Fort Riley, on the Kansas River, and passing a little eastward traversed Minnesota to the British possessions, near the head of Lake Superior. The extent of sea to the westward was vast, and geology has not yet laid down its boundary; it was probably a shore now sub- merged beneath the waters of the North Pacific Ocean. 7 Far out on the expanse of this ancient sea might have been seen a. huge, snake-like form, which rose above the surface and stood erect, with taper- ing throat and arrow-shaped head, or swayed about, describing a circle of twenty feet radius above the water. Then plunging into the depths, naught would be visible but the foam caused by the disappearing mass of life. Should several have appeared together, we can easily imagine tall, flexible forms rising to the height of the masts of a fishing-fleet, or like snakes, twisting and knotting themselves together. This extraordinary neck—for such it was—rose from a body of elephantine proportions, and a tail of the serpent-pattern balanced it behind. The limbs were probably two pairs of paddles like those of Plesiosaurus, from which this diver chiefly differed in the arrangement of the bones of the breast. In the best-known species, twenty-two feet represent the neck in a total length of fifty feet. This is the Elasmosaurus platyurus, Cope, a carnivorous sea-reptile, no doubt adapted for deeper waters than many of the others. Like the snake-bird of Florida, it probably often swam many feet below the surface, raising the head to the distant air for a breath, then withdrawing it, and exploring the depths forty feet below, without altering the position of its body. From the localities in which the bones have been found in Kansas, it must have wandered far from 45 land; and that many kinds of fishes formed its food is shown by the teeth and scales found in the position of its stomach. A second species of somewhat similar character and habits differed very mach in some points of structure. The neck was drawn out to a wonderful degree of attenuation, while the tail was relatively very stout, more so, indeed, than in the E~/asmosaurus, as though to balance the anterior regions while occupied in various actions; e. g., while capturing its food. ‘This was a pow- erful swimmer, its paddles measuring four feet in length, with an expanse, therefore, of about eleven feet. It is known as Polycotylus latipinnis, Cope. The two species just described formed a small representation, in our great interior sea, of an order which swarmed, at the same time or near it, over the gulfs and bays of old Europe. There they abounded twenty to one. Per- haps one reason for this was the almost entire absence of the real rulers of the waters of ancient America, viz, the Pythonomorphs. These sea-serpents— for such they were—embrace more than half the species found in the lime- — stone-rocks in Kansas, and abound in those of New Jersey and Alabama. Only four have been seen as yet in Europe. Researches into their structure have shown that they were of wonder- ful elongation of form, especially of tail; that their heads were large, flat, and conic, with eyes directed partly upward; that they were furnished with two pairs of paddles like the flippers of a whale, attached by short wide peduncles to the body. With these flippers and the eel-like strokes of their flattened tail, they swam, some with less, others with greater speed. They were furnished, like snakes, with four rows of formidable teeth on the roof of the mouth. Though these were not designed for mastication, and, without paws for grasping, could have been little used for cutting, as weapons for seizing their prey they were very formidable. And here we have to consider a peculiarity of these creatures, in which they are unique among animals. Swallowing their prey entire like snakes, they were without that wonderful expansibility of throat due in the latter to an arrangement of levers support- ing the lower jaw. Instead of this, each half of that jaw was articulated or jointed at a point nearly midway between the ear and the chin. This was of the ball-and-socket type,and enabled the jaw to make an angle outward, and thus widen by much the space inclosed between it and its fellow. The arrangement may be easily imitated by directing the arms forward, with the elbows turned outward, and the hands placed near together. The ends of these bones were 46 in the Pythonomorpha as independent as in the serpents, being only bound by flexible ligaments. By turning the elbows outward and bending them, the space between the arms becomes diamond-shaped and represents exactly the expansion seen in these reptiles, to permit the passage of a large fish or other body. The arms, too, will represent the size of jaws attained by some of the smaller species. The outward movement of the basal half of the jaw neces- sarily twists in the same direction the column-like bone to which it is sus- pended. The peculiar shape of the joint by which the last bone is attached to the skull depends on the degree of twist to be permitted, and therefore to the degree of expansion of which the jaws were capable. As this differs much in the different species, they are readily distinguished by the column or ‘“‘quadrate” bone when found. These are some curious consequences of this structure, and they are here explained as an instance of the mode of recon- struction of extinct animals from slight materials. The habit of swallowing large bodies between the branches of the under jaw necessitates the prolonga- tion forward of the mouth of the gullet; hence the throat in the Pythono- morpha must have been loose and almost as baggy as a pelican’s. Next, the same habit must have compelled the forward position of the glottis or open- ing of the windpipe, which is always in front of the gullet. Hence these creatures must have uttered no other sound than a hiss, as do animals of the present day which have a similar structure; as, for instance, the snakes. Thirdly, the tongue must have been long and forked, and for this reason: its position was still anterior to the glottis, so that there was no space for it except it were inclosed in a sheath beneath the windpipe when at rest, or thrown out beyond the jaws when in motion, Such is the arrangement in the nearest living forms, and it is always in these cases cylindric and forked. The giants of the Pythonomorpha of Kansas have been called Liodon proriger, Cope, and Liodon dyspelor, Cope. The first must have been abundant, and its length could not have been far from seventy-five feet; certainly not less. Its physiognomy was rendered peculiar by a long projecting muzzle, remind- ing one of that of the blunt-nosed sturgeon of our coast; but the resemblance was destroyed by the correspondingly massive end of the branches of the lower jaw. Though clumsy in appearance, such an arrangement must have been effective as a ram, and dangerous to his enemies in case of collision. The writer once found the wreck of an individual of this species strewn around a sunny knoll beside a bluff, and his conic snout pointing to the 47 heavens formed a fitting monument, as at once his favorite weapon, and the mark distinguishing all his race. The Liodon dyspelor was probably the longest of known reptiles, and probably equal to the great finner-whales of modern oceans. The circumstances attending the discovery of one of these will always be a pleasant recollection to the writer. A part of the face, with teeth, was observed projecting from the side of a bluff by a companion in exploration, Lieut. James H. Whitten, United States Army, and we at once proceeded to follow up the indication with knives and picks. Soon the lower jaws were uncovered, with their glistening teeth, and then the vertebra and ribs. Our delight was at its height when the bones of the pelvis and part of the hind limb were laid bare, for they had never been seen before in the species, and scarcely in the order. While lying on the bottom of the Creta- ceous sea, the carcass had been dragged hither and thither by the sharks and other rapacious animals, and the parts of the skeleton were displaced and gathered into a small area. The massive tail stretched away into the bluff, and, after much laborious excavation, we left a portion of it to more persever- ing explorers. The discovery of a related species (Platecarpus corypheus, Cope) was made by the writer under circumstances of difficulty peculiar to the plains. After examining the bluffs for half a day without result, a° few bone-fragments were found in a wash above their base. Others led the way to a ledge forty or fifty feet from both summit and foot, where, stretched along in the yellow chalk, lay the projecting portions of the whole monster. A con- siderable number of vertebree were found preserved by the protective embrace of the roots of a small bush, and, when they were secured, the pick and knife were brought into requisition to remove the remainder. About this time, one of the gales, so common in that region, sprang up, and, striking the bluff fairly, reflected itself upward. So soon as the pick pulverized the rock, the limestone-dust was carried into eyes, nose, and every available opening in the clothing. I was speedily blinded, and my aid disappeared in the caiion, and was seen no more while the work lasted. A handkerchief tied over the face, and pierced by minute holes opposite the eyes, kept me from total blindness, though dirt in abundance penetrated the mask. But a fine relic of creative genius was extricated from its ancient bed, and one that leads its genus in size and explains its structure. On another occasion, riding along a spur of a yellow chalk-bluff, some vertebree lying at its foot met my eye. An examination showed that the series 48 entered the rock, and, on passing round to the opposite side, ‘the jaws and muzzle were seen projecting from it, as though laid bare for the convenience of the geologist. The spur was small and of soft material, and we speedily removed it in blocks, to the level of the reptile, and took out the remains as they lay across the base from side to side. A genus related to the last is Clidastes. They did not reach such a size as some of the Liodons, and were of elegant and flexible build. To prevent their contortions from dislocating the vertebral column, these had an addi- tional pair of articulations at each end, while their muscular strength is attested by the elegant strize and other sculptures which appear on all their bones. Ten species of this genus occur in the Kansas strata, the largest (Clidastes cineriarum, Cope) reaching forty feet in length. A smaller species, of elegant proportions, has been called C. tortor, Cope. Its slenderness of body was remarkable, and the large head was long and lance-shaped. Its lithe movements brought many a fish to its knife-shaped teeth, which are more efficient and numerous than in any of its relatives. It was found coiled up beneath a ledge of rock, with its skull lying undisturbed in the center. A species distinguished for its small size and elegance, is C. pumilus, Marsh. This little fellow was only twelve feet in length, and was probably unable to avoid occasionally furnishing a meal for some of the rapacious fishes which abounded in the same ocean. The flying saurians are pretty well known from the descriptions of European authors. Our Mesozoic periods had been thought to have lacked these singular forms until Professor Marsh and the writer discovered remains of species in the Kansas chalk. Though these are not numerous, their size was formidable. One of them (Pterodactylus occidentalis, Marsh) spread eighteen feet between the tips of its wings, while the P. wmbrosus, Cope, covered nearly twenty-five feet with his expanse. These strange creatures flapped their leathery wings over the waves, and, often plunging, seized many an unsuspect- ing fish; or, soaring at a safe distance, viewed the sports and combats of the more powerful saurians of the sea. At night-fall, we may imagine them trooping to the shore, and suspending themselves to the cliffs by the claw- bearing fingers of their wing-limbs. Tortoises were the boatmen of the Cretaceous waters of the eastern coast, but none had been known from the deposits of Kansas until very recently. The largest species on record (Protostega gigas, Cope) is strange 49 enough to excite the attention of naturalists. It is well known that the house or boat of the tortoise or turtle is formed by the expansion of the usual bones of the skeleton till they meet and unite, and thus become continuous. Thus the lower shell is formed of united ribs of the breast and of the breast-bone, with bone deposited in the skin. In the same way, the roof is formed by the union of the ribs with bone deposited in the skin. In the very young tortoise, the ribs are separate as in other animals; as they grow older, they begin to expand at the upper side of the upper end, and with increased age the expansion extends throughout the length. The ribs first come in contact, where the process commences, and in the land- tortoise they are united to the end. In the sea-turtle, the union ceases a little above the ends. The fragments of the Protostega were seen by one of the men projecting from a ledge of a low bluff. Their thinness and the distance to which they were traced excited my curiosity, and I straightway attacked the bank with the pick. After several square feet of rock had been removed, we cleared up the floor, and found ourselves well repaid. Many long, slender pieces of two inches in width lay upon the ledge. They were evidently ribs, with the usual heads, but behind each head was a plate like the flattened bowl of a huge spoon, placed crosswise. Beneath these stretched two broad plates, two feet in width, and no thicker than binder’s board. The edges were fingered, and the surface hard and smooth. All this was quite new among fully-grown animals, and we at once determined that more ground must be explored for further light. After picking away the bank, and carving the soft rock, new masses of strange forms were disclosed. Some bones of a large paddle were recognized, and a leg-bone. The shoulder-blade of a huge tortoise came next, and further examination showed that we had stumbled on the burial-place of the. largest species of sea-turtle yet known. The single bones of the paddle were eight inches long, giving the spread of the expanded flippers as considerably over fifteen feet. But the ribs were those of an ordinary turtle just hatched, and the great plates represented the bony deposit in the skin, which, commencing independently in modern turtles, unites with each other at an early day. But it was incredible that the largest of known turtles should be but just hatched, and for this and other reasons it has been con- cluded that this ‘ancient mariner” is one of those forms not uncommon in old days, whose incompleteness in some respects points to the truth of the belief that animals have assumed their modern perfections by a process of growth from more simple beginnings (Ro 50 The Cretaceous ocean of the West was no less remarkable for‘its fishes than for its reptiles. Sharks do not seem to have been so common as in the old Atlantic, but it swarmed with large predaceous forms related to the salmon and saury. Vertebree and other fragments of these species project from the worn limestone in many places. I will call attention to perhaps the most formida- ble as well as the most abundant of these. It is the one whose bones most frequently crowned knobs of shale, which had been left standing amid sur- rounding destruction. The density and hardness of the bones shed the rain off on either side, so that the radiating gutters and ravines finally isolated the rock mass from that surrounding. The head was some inches longer than that of a fully-grown grizzly bear, and the jaws were deeper in proportion to their Iength. The muzzle was shorter and deeper than that of a bull-dog. The teeth were all sharp cylindric fangs, smooth and glistening, and of irreg- ular size. At certain points in each jaw they projected three inches above the gum, and were sunk one inch into deep pits, being thus as long as the fangs of a tiger, but more slender, Two pairs of such fangs crossed each other on each side of the end of the snout. This fish is known as Portheus molossus, Cope. Besides the smaller fishes, the reptiles no doubt supplied the demands of its appetite. The ocean in which flourished this abundant and vigorous life was at last ‘completely inclosed on the west by elevations of sea-bottom, so that it only communicated with the Atlantic and Pacific at the Gulf of Mexico and the Arctic Sea. The continued elevation of both eastern and western shores contracted its area, and when ridges of the sea-bottom reached the surface, forming long, low bars, parts of the water-area were inclosed, and connection with salt-water prevented. Thus were the living beings imprisoned and sub- jected to many new risks to life. The stronger could more readily capture the weaker, while the fishes would gradually perish through the constant freshening of the water. With the death of any considerable class, the bal- ance of food-supply would be lost, and many larger species would disappear from the scene. The most omnivorous and enduring would longest resist the approach of starvation, but would finally yield to inexorable fate; the last one caught by the shifting bottom among shallow pools, from which his exhausted energies could not extricate him. 1834. 1845. 1856. 1860. 1868. 1869. 1870. D1 REPTILIA. LITERATURE OF THE SUBJECT. Harlan, in Transactions of the American Philosophical Society, v. LV, p- 405, pl. xx, figs. 83-8. Mosasaurus missuriensis. Snout de- scribed. Goldtuss, in Nova Acta Acad. K. L. C. Nat. Cur., X XI, p. 179, pls. vi, vii, vili, ix. Mosasaurus maximiliani described (with malar arch) (possibly remaining part of Harlan’s specimen). Leidy, in Proceedings of the Academy of Natural Sciences, Philadel- phia, p. 8%. Ischyrosaurus antiquus described. Leidy, /. sup. c., p. 73; six species of reptiles from the Fort Union beds of Judith River described. Leidy, @ sup. c., p. 311. Hadrosaurus occidentalis and two tortoises from the same beds described. Leidy, Transactions of the American Philosophical Society, p.145. All the species of the Fort Union epoch redescribed and figured. Cope, in Leconte’s Notes on the Geology of the Extension of the Union Pacific Railroad, Eastern Division, on the Smoky Hill, p. 68. Elasmosaurus platyurus described. Cope, in Proceedings of the Boston Society of Natural History, p. 250. January (separata). The order Pythonomorpha defined ; the num- ber of cervical vertebrae, structure of the posterior regions of the cranium, of the lower jaw, scapular arch, and fore-limb first deter- mined; genus Platecarpus defined. Cope, in Proceedings of the American Philosophical Society, June. Articulation of splenial bone in Pythonomorpha described; genus Polycotylus described. Cope, Transactions of the American Philosophical Society. Part I of Synopsis of Extinct Batrachia, Reptilia, and Aves of North Amer- ica (to p. 104), issued in August. Hlasmosaurus and Polycotylus described and Reptilia of Fort Union epoch determined. Cope, in Transactions of the American Philosophical Society, same work, part II (to p. 235), issued in April. Order Pythonomorpha further described, its genera further defined, and Liodon proriger described. : 52 Cope, Proceedings of the American Philosophical Society, p.574. Lio- don dyspeior, Platecarpus mudget, P. ictericus, and Clidastes cineria- rum described. Marsh, in American Journal of Science and Arts, p. 472 (separata June). Pelvis of Pythonomorpha first described, and the hind limbs for the first time stated to exist, and the species Clidastes dispar, velox, vymanii, and pumilus, and Pterodactylus owenii described. Cope, in letter to J. P. Lesley, in Proceedings of the American Philo- sophical Society, p. 168 (separata October). Hind limb of a Py- thonomorph first described, and Platecarpus latispinus and P. cras- sartus described. Cope, 7. c., p. 172 (separata October). Protostega described, with hind limbs and pelvis of Liodon dyspelor. Testudinata first recorded. Cope, ¢. c., p. 264, December. Catalogue of Pythonomorpha found in the Cretaceous strata of Kansas. Pterygoid bones first. deter- mined, and hind limbs described; genera determined, and six new species described. Cope, /.c., p. 808 (separata January). Cynocercus incisus and Hyposaurus vebbw described. Marsh, American Journal of Science and Arts (separata March 9). Pterodactylus ingens and P. velox described. Name of P. owenii changed to P. occidentalis. Scuta of Pythonomorpha described. Cope, Proceedings of the American Philosophical Society (separata March 11). Pterodactylus umbrosus and P. harpyia described. Cope, @. c., p. 403 (separata March). Protostega gigas fully described, and southern and eastern species named. Marsh, American Journal of Science and Arts (separata May). Deter- mination of position of phalanges of fore-limb, and of two addi- tional bones connected with the opisthotic in Pythonomorpha; cor- rection of position of the quadrate and confirmation of the previous locations of the malar arch and stapes; description of six new spe- cies, and better definition of the genera Platecarpus and Liodon. Cope, in Proceedings of the Academy of Natural Sciences, Philadel- phia (separata June 6th). Description of Plestosaurus gulo. Cope, in ¢. sup. c. (separata June 8th). Review of Professor Marsh’s paper of May, 1872; corrections of questions of nomenclature and discovery. Cope, in Proceedings of the American Philosophical Society (separata August 12). Genus Agathaumas described. 1873. Cope, Proceedings of the Academy of Natural Sciences, Philadelphia, p. 10. Toxochelys latiremis described. Leidy, Report of the United States Geological Survey of the Territo- ries, by F. V. Hayden. CVidastes affinis and Plesiosaurus occiduus described and other known species figured. 1874. Cope, in Hayden’s Bulletin of the United States Geological Survey of the Territories, No. 2 (issued April). Species of Cionodon, Polyonaz, Bottosaurus, Trionyx, Plastomenus, Adocus, Clidastes, and Liodon described ; structure of Dinosauria of the Fort Union epoch eluci- dated. : DINOSAURIA. AGATHAUMAS, Cope. Proceedings of the American Philosophical Society, 1872, p. 482. The characters of this genus are derived from the typical species A. sy/- vestris, which is represented by dorsal and lumbar vertebrae and an entire sacrum, with the ilia, one nearly entire, ribs, and a number of other bones the character of which have not yet been positively ascertained. One of these resembles the proximal part of the pubis; others, portions of the sternum, &e. On eight (and, perhaps, nine) vertebra, anterior to the sacrum, there is no indication of the capitular articular facet for the rib. This facet is found, as in Crocodilia, at or near the base of the elongate diapophyses. The centra are slightly concave posteriorly, and still less so on the anterior face, with gently convex margins. The neural canal is very small, and the neural arch short, and quite distinct from the centrum, having scarcely any suture. The neural arch has a subcubical form, partly truncated above by the anterior zygapophyses. In like manner, the base of the combined neural spine and dia- pophyses are truncated below by the square-cut posterior zygapophyses. The diapophyses are long, and directed upward; they are triangular in section. There are eight (and, perhaps, nine) sacral vertebree, which exhibit a con- siderable diminution in the diameters of the centra. The diapophyses and neural arches are shared by two centra, the anterior part of a centrum bear- ing the larger portion of both. The diapophyses are united distally in pairs; each pair inclesing a large foramen. The anterior is the most massive D4 rest on the ilium; the posterior pair the most expanded; the superior mar- gins of its posterior edge form an open V, with the apex forward on the neural arch of the fifth vertebra. On the last sacrals, the diapophyses rise to the neural arch again. The exits of the sacral spinal nerves are behind the middles of the centra, and continue into grooves of the sides in all but the last vertebree. The reduced and rather elongate form of the last sacral verte- bra induces me to believe that this animal did not possess such large and short caudal vertebree as are found in the genus Hadrosaurus, and that the tail was a less massive organ. The ium is much more elongate than the corresponding element in Hadrosaurus, Cetiosaurus, or Megalosaurus. Its upper edge is turned and thickened inward above the anterior margin of the acetabulum, and here the middle of the conjoined diapophyses of the second and third sacral vertebree was applied when in place. In front of this point, the ilium is produced in a straight line and a stout flattened form with obtuse end. Posterior to it, its inner face is concave to receive the second transverse rest of the sacrum, and the superior margin is produced horizontally toward the median line like the corresponding bone in a bird. ‘The posterior part of the bone is the widest; for it is expanded into a thin plate and produced to a considerable length. From one of the margins (my sketch, made on the ground, represents it as the upper), a cylindric rod is produced still farther backward. This it is believed is only the shaft of a displaced rib. The base of the ischium is co- ossified with the ilium, and is separated behind its base from the iliae portion of the acetabulum. ‘There is no facet nor suture for the pubis at the front of the acetabulum. The ribs are compressed. There are no bones certainly referable to the limbs. The form of the ilia distinguishes this genus from those known hereto- fore. AGATHAUMAS SYLVESTRIS, Cope. Proceedings of the American Philosophical Society, 1472, p. 422. The last nine dorsal vertebree have rather short centra; the most poste- rior the shortest. They are higher than wide; the sides are concave, the in- ferior face somewhat flattened. The neural arch is keeled behind from the canal to between the posterior zygapophyses, and a similar keel extends from the base of the neural spine to hetween the anterior zygapophyses. The 5D neural spine is elevated and compressed; the diapophysis is convex above and concave along the two inferior faces, most so on the posterior. The articular face of the first sacral vertebra is wider than deep. The eight sac- ral vertebree are flattened below, in all except the first, by a plane which is separated from the sides by a longitudinal angle. The neural spines of the anterior five sacral vertebree are mere tuberosities. A large sutural surface for attachment of a transverse process is seen on the posterior third of the eighth sacral vertebra, which descends nearly as low as the plane of the in- ferior surface. On the ? tenth sacral, there is no such process, but its neural arch and that of the ! ninth support transverse processes. ‘These are more like those of the dorsals in having three strong basal supporting ribs, the anterior and posterior extending for some distance along the arch. Either naturally, or in consequence of distortion, the plate of the ihum is at a strong angle to the vertical axis of the acetabulum, and at the posterior part of it its plate presents a free margin on the outside as well as the inside of the femoral articulation. Measurements. . M. Length of the nine posterior dorsal vertebra).- ---- 2... 22 - «2. - =~ one wen ene ee nee one ene eae ne 0. 880 Geneth of the nineisacral’ vertebrae (86% inches)/- .2.5-< a. ssc on nisiveicone soicees vamine= se = = eoce 0. 930 Length of right ilinm (two pieces, 0.84--0.22), (41 inches)..---.-..--..-.-.--------------------- 1. 060 Length of eighth dorsal from the sacrum....-.....-.------ 20-226 oes 02 eee ens cone vee eee ene ne 0. 090 enucthiomblieybase ofthemeurapophysisieas-scise sas jeeeee cide siecle cise closet cciseenee eaacine acces 0. 085 Wenihvofeuherarticul ayia ceseseceeeee races eae eeere eases SOE AE ae So ie eee eee 0.153 Widthvotitherarticulantace seems ates eacte eee seciee alsa eee ees tica stem ceiciciccccie see as 0. 123 Wenge thvofsthe secon dyiromisAc rom erect eae lee eee tee cleat eey- alee eee ae ease ONOZO DG OIF WHS GATCMIERE HCC s cooseo dst oSouscoud oes DESO cREe ood UNOS send EdnS Seao sane poco cauaccse 0. 155 Wiudthtotethevanti cull piacere terrae sete anaeaerssieieter (eit eet sae ete aie eer eeieetaarseie aeenerae screen OO T, Blevatroncof thesnenLal geal Septet te elope ya cote ose tea ee se ee eS ES SEO A Madthvomthemeuralscom al bereme rere salar aeicicasteiceeey ciseniieecioae eiaeeiseticnescceieseres 0. 028 Mlevahiontolthewaceotuhe zyoapophysesnassasaeen= eles ele iota eae ee one ieee nese eeeisacee. 0. 104 Hlevationsto thebaseotuhemeunralispines sere rseree cicero eeeoere ee cectces ceeeeee eee eee eee 0.150 Length of the diapophysis from the lower base.........----. --.--------- SCE SEES Maer ees 0. 200 Length of the diapophysis from the capitular articulaticn -..-.---...---. 2-2. e--- 2--- 02-2 eee 0.125 ATiteLo-pOsteLiorawi dthabovescmaes = enseeeesisaeth ese serle years acces abodes poaoos Sco ce peesce 0. 05 Antero-posterior width of the base of the neural spine..---.. ...--. -.---- e.------------0--- wee 0. 070 Antero-posterior width at the zysapophysis--.-.-. -.---- 2222-22. saee wane ene emcees one e enn 0.078 igen othyot themenuralispinex (roo men) eae es eee seer cease ee eel sseeeseeeenemeeee eer eee a Os 200 Width oftheicentrum) of. theirstisacriullss-sereme> ss -iseee = eles eeeeee cece eae SENG 2 ARROE eae 0. 160 Depth of the centrum of the first sacral (to the neurapophysis)--.-..-.-.-.-.-.---.-.---.-.---.-- 0.145 eng thiofphercentnimyoteche nits isa Cra eesaprtee sees eats eer ere seee cine ee eee eis 0.100 engthiotthercentrumiofiheseyenthis icra lee = seis = atpecisa fei sents aa siee aise haa ae te = ae 0. 100 Depth of the centrum of the seventh sacral (behind). -:---.-. 2-2. 1.22222 - ones 2 coe nee eon one 0. 085 , Width of the centrum of the seventh sacral (behind) -...---..--.----.-.--------.---- Roe Ree 0.100 Expanse of the second sacral transverse support (22 inches)..---.--..----.--.---.-----------.-- 0. 560 Length of the ilium anterior to the acetabulum ..........-.--...---.-.---2----2--------------- 0.470 enothvoftheace tab ulumpescererteeeetetee setae cae et eeaee ante rales a aaa esissiaiaei a) eae ise =e OS 200) Length of the ilium posterior to the acetabulum. ...--...---.-----.---- ------ se 2-2) eee e ee esse 0.390 WichMombhenlinniaathh eran beriomexirennl tuyere ere tep catia aisle iar ete esi eile is sissies see 0.140 M. Wadthiof theilium atithe front of theiacetabulum------.------.-----cces sos sens cess cone seco ee 0. 210 iWadthtofethewliumsatithe posterior/expansiones sss see mee eecces == en aceae eceecre cee e eoene eee 0. 250 GNinclengss Howe We Heal OMIT = scoaecocco oe cnao Se ceud sone cago bao Soo DOEEoS coo dee SoEeEO oo cas 0. 060 Widthyofstheracetabwlmm yee csc se cscs sinters sinister se se ees saci ons ens som ese nese ena eee 0.105 Waidthtortathesbasistotibhenschiumeeessasseerse lee eae tece ema akeaneccem tee eaeee mee eee eee ree 0. 085 Width OF UNS CANE OF @ MID. coon endees oaeees code anes ancoes Secese HsEESH JeascecanSsses Uas0 SuS5se 0. 062 Other bones, not yet determined, will be included in the description in the final report. This species was no doubt equal in dimensions to the largest known ter- restrial saurians or mammals. HADROSAURUS, Leidy. HADROSAURUS MIRABILIS, Leidy. Numerous bones of Dinosauria, from the Milk River, British America, submitted to me by Dr. G. M. Dawson, of the British North American Boundary Commission, embrace specimens appropriate to this species, but not certainly referable to it. The locality is nearer to the bad lands of Judith River, from which the H. mirabilis was procured, than to any other exposure of the Fort Union beds. There are portions of femora, humeri, and ilia, but the only piece suffi- ciently characteristic for description is a median caudal vertebra. The inferior ridges and facets for chevrons are strongly developed; the latter appearing at both ends. The anterior articular face is plane ; the posterior, concave. ‘The centrum is deeper than wide, slightly narrowed below; no traces of diapophyses. Length, 0".060; depth of articular face, 0".077; width of articular face, 0".071; length of base of neural arch, 0.038. The reference of this vertebra is uncertain, but it seems too small for the HZ. occi- dentaiis, although in the opisthoceelian character it is similar. HApRoOsaURUS OCCIDENTALIS, Leidy. Referred by Professor Leidy to a distinct genus under the name of Thespesius, on account of the slightly opisthoceelian character of the large caudal vertebree. Teeth unknown. Fragments of a large Dinosaur, from Colorado, were found associated with species of tortoises identical with those found in Dakota, in the horizon which contains the H. occidentalis (see under head of Cionodon arctatus), and may possibly belong to it. I have no identical parts in the two for com- parison. 57 Char. specif—The largest fragment of a long bone is probably from the proximal end of the tibia; it includes the curved border of the inner side, and the inner posterior tuberosity, with five inches of the inner side of the shaft. The superficial layer is marked with numerous closely-placed longitudinal grooves, which are replaced at intervals by a few coarser and deeper ones, which interrupt the angle with the articular surface, giving it a lobate margin. There was probably a prominent cnemial crest. Another fragment exhibits one flat plane, and a concave posterior face. It comes from near the extremity of the humerus or the femur; it was found near the fragment of the tibia. The sacral vertebra is probably that of an animal not fully grown, as it was not co- ossified with those adjacent. The articular extremities are expanded, and pre- sent distinct faces for articulation for the large diapophyses. The one extremity is more expanded and less thickened, the other more thickened and less dilated; on this rests the greater part of the base of the neural arch. Just at the extremity of this base, the large sacral nervous foramen issues, which is continued in a wide groove downward between the transverse expansions. Inferior surface convex. As compared witli the fourth sacral vertebra of Agathaumas sylvestris, Cope, which it nearly resembles in size, it is to be observed that the anterior extremity is less expanded transversely as compared with the posterior ; that the bases of support for the anterior diapophyses are not produced downward so far; that the sides of the centrum are nearly ver- tical, and not sloping obliquely toward the middle line; and that there is no inferior plane separated from the lateral by a longitudinal angle, as in A. sylvestris. Tt differs in like manner from the third and second sacral verte- bree, and still more from the first of the latter saurian. Measurements. M. Length of the centrum of the fourth sacral vertebra ....---..--- 2. 2-22 2-22 oo eee ee oe ne 0. 092 Transverse diameter: JENA Re eA se aidcias BUDO Obed BE BSEe SOcd oe 5, GSH AOU ERC Hoe: SRE EAS SE RCabasabbasan mass 0. 103 Ab Middloyscaassaaac tec osmae soe Sse ees Sos ei tain cei Occ ssieweee ete scbeereeebee 0. 072 POStOTI OT iy ere aa teu este ropsia sree See eT oe Cee eee eee oe nic oie eee ce meeten ie ie tiselsmtommce nts 0.121 Verticalidiameter,posterionlyens ses tees seats oe aetaceee haces eee seetace cise sees eae eae 0. 092 Diameter of the head of the tibia, antero-posteriorly...-....---.-.---.----2- ---+ s+ +--+ = ------ 0. 250 CIONODON, Cope. Bulletin of the United States Geological Survey of the Territories, No. 1, 1874, p. 2. Remains of species of Dinosauria were obtained at two localities in Colorado, not many miles apart; the greater number at one of them, from 8c 58 which also all the crocodilian and turtle remains were derived. Those from the other deposit consist of portions of limb-bones, apparently of a single individual of gigantic size. The more abundant fragments are referable to three species. A fragment of a limb-bone is very similar to portions from the other locality, and asseciated is a sacral vertebra of appropriate size and characters. All of these were, therefore, referred provisionally to a single species under the name of Agathaumas milo, but are here described under Hadrosaurus occidentalis. The remaining specimens fall into two series. In “the one, the bones are occupied by a heavy mineral, and the surfaces covered by a white layer, which is marked by irregular ridges, as though produced by deposit along the lines of small adherent foreign bodies. In the other set, the bones are lighter, more spongy, and not covéred with the white layer; some of them are stained by the sesquioxide of iron. Both present vertebrae and limb-bones, which are related appropriately as to size and structure; that is, the larger limb-bones have the same mineral character as the larger verte- bree, and the smaller as the smaller. These limb-bones represent correspond- ing parts in the two, and, differing widely, confirm the belief in the existence of two species derived from the different types of vertebree. In these fossils, then, I see evidence for the existence of two species of two genera, which I name—the larger, Polyonax mortuarius; the smaller, Cionodon arctatus. Both genera present a solid, cancellous filling of femora, tibiz, and other long bones, and hence differ from such genera as Hadrosaurus, Hypsibema, Le@laps, and others. Czonodon differs in dentition from all Dinosauria where that part of the structure is known; but it remains to compare Polyonazx with Troidon and- Pa/@oscincus of Leidy, which are known from the teeth only, while no portions of dentition are preserved with the specimens at my disposal. Char. gen —KEstablished primarily on a portion of the right maxillary bone, with numerous teeth in place. The posterior portion exhibits a suture, probably for union with the palatine bone, while the rest of the interior margin is free. It is removed some distance from the tooth-line in consequence of the horizontal expanse of the bone, while the outer face is vertical. The teeth are rod-like; the upper portion subcylindric in section, with the inner face flattened from apex to base, whiie the lower half is flattened by an abrupt excavation to the middle, for the accommodation of the crown of the successional tooth. The inner face of the tooth, from apex to base, is shielded by a plate of enamel, which is somewhat elevated at the margins, and o9 supports a keel in the middle, thus giving rise to two shallow longitudinal troughs. The remainder of the tooth is covered with a layer of some dense substance, possibly cementum, which overlaps the vanishing margins of the enamel. The outer inferior excavation of the shaft presents a median longitud- inal groove to accommodate the keel of the closely-appressed crown of the successional tooth. The apex of the tooth being ob- tusely wedge-shaped, the func- tional tooth is pushed forward and transversely toward the inner side of the jaw. The tooth slides downward ina closely-fitting ver- Fie. 1.—Diagram of the maxillary dentition of Cionodon arctatus: a, grinding-face ; b, superior or radical view of tical groove of the outer alveolar the maxillary bone, natural size. wall. The inner wall is oblique, its section forming with that of the outer a V; it is furrowed with grooves similar and opposite to those of the outer wall, but entirely disconnected from them. The base of the shank of the functional tooth, on being displaced by the successional, slides downward and inward along the groove of the inner side; each lateral movement being accompanied by a corresponding protrusion. At the most, three teeth form a transverse line; namely, one new apex external, one half-worn crown median, and the stump or basis of a shank on the inner. The new crowns are, however, pro- truded successively in series of three in the longitudinal direction also. Thus, when an apex is freshly protruded, the shank in front of it is a little more prominent, and the third stands beyond the alveolar border. As each shank increases somewhat in diameter downward in the C. arctatus, the section increases in size with protrusion ; hence, before the appearance of a new crown outside of it, there are but two functional teeth in a cross-row. Thus, in the outer longitudinal row, only every third tooth is worn by functional use at one time; in the middle series, all are in use; while, in the inner, every third one is simultaneously thrown out in the form of a minute stump of the shank, if not entirely ground up. The dorsal vertebra are opisthoccelian, the anterior more compressed 60 than the posterior; capitular articular faces, if existing, are slightly marked. The zygapophyses are but little prominent beyond the arch. A caudal verte- bra is plano-concave, with rather depressed centrum, a little longer than broad. The condyles of the femur have a short are and chord; the head of the tibia displays a large cnemial crest, but is not emarginate behind. The type of dentition exhibited by this genus is, perhaps, the most com- plex known among reptiles, and is well adapted for the comminution of vege- table food. While the mechanical effect is quite similar to that obtained by the structure of the molars of ruminating mammals, the mode of construction is entirely altered by the materials at hand. Thus, the peculiarly simple form and rapid replacement of the reptilian dentition is, by a system of complica- tion by repetition of parts, made to subserve an end identical with that secured by deep plication of the crown of the more specialized molar of the mammal. Cionodon is evidently allied to Hadrosaurus, but displays greater dental complication. In that genus, according to Leidy, the successional crowns appear on the front side of the shank of the tooth, not behind, and below the base of the enamel-area, so that the tooth is distinguished into crown and shaft. It also follows, from this arrangement, that the successional tooth does not appear until its predecessor has been worn to the root, in which case there can be only one functional tooth in a transverse section, instead of two or three. Cronopon ARCcTATUS, Cope. Bulletin, l. ¢., p. 2. Char. specif—The enamel-plate of the tooth extends from apex to near the base of the shaft. Its margins are thickened and without serration, while the surface generally is nearly smooth. ‘The dense layer over the remainder of the tooth is much roughened by a great number of short, serrate, and somewhat irregular longitudinal ridges. Measurements. M. Width of the alveolar groove..---..-.--. ---------------------- J low ds See en ee 0.0120 Length of a triad of teeth on the alveolus....---. ~--.---------------------------++ +--+ +--+ 0.0140 Length of an unworn tooth ...--..----:.--- ----++ «+--+ + - +++ 222 eee eee eee rece en eee 0, 0250 Diameter of the surface of attrition of a tooth uf the middle row : Longitudinal ...----.----------.---------------- Sea yess 932 2 ott ssecer: 0. 0063 TT PANKVOIRG ane cee ce aces cocinthe ae cefani eee ae Sep elem inlet eeleiot= =a iai~in lin Sle elivimin lms Sse 0. 0072 Width of the maxillary bone.-..-.-- -------. ------ ------ ---- -- «=~ oe oan ee eee owns 0.0350 Depth of the maxillary bone at the INNER MALU oa eee oem en 0. 0140 61 What I suppose to be the posterior end of the maxillary bone exhibits the grooves to near its apex as well as a considerable surface of articulation for the malar. Two dorsal vertebre are preserved, whose neural arches are codssified, with a trace of the suture remaining. Both articular faces exhibit a transverse fossa for ligamentous or bursary attachment. Round these, on the convex face, there are transverse rugosities, while oblique-ridged lines descend on each side from the floor of the neural canal. The centra are shorter than deep, and subquadrate in a horizontal section. The sides are concave; the anterior one compressed with lenticular vertical section with the angle below. The more posterior is less compressed, and the surface is smooth ; in the an- terior, it is thrown into weak longitudinal ridges near the edges of the articular extremities. There are large nutritious foramina on the sides. The neura- pophyses are excavated vertically on their posterior edges. Neural canal on the anterior dorsal, a broad vertical oval. A caudal vertebra is rather elongate and depressed ; as it has no diapophysis, it is not from the anterior part of the series. There is no prominent lateral angle, but the two inferior angles con- necting the chevron-facets are well marked. Neurapophysis only measuring half the length of the centrum. The articular faces exhibit the same trans- verse fossa as is seen in the dorsals. ‘The anterior is plane, the posterior reniformly concave. Measurements. Anterior dorsal : ° M. jreng throfsathercen tru mcese recess cetera s ae evar io el ey oe tee nee eS IN ath aleve 0. 074 Plevationvofathevarticu] ar taceecse soccer operas tere leprae ee cre oR ene eg eer 0.073 IWidthvomtherarticularifacessesyasccs secs cite ere ee rete rials ea oi eee eee ee ee eeeeae 0. 070 Verticaltdiametenotsthemenuraltcanaleerse eee ceer eerie near ee eee eee eee eee 0. 027 Elevation of the anterior zygapophyses-.-...-.-.--.-....-------+------ Bahn wis Read seers 0. 122 Middle dorsal : Then gthvotathel centromere senescence ates eee eee eee eee nee eee ee ie ee On0GS Blevation\ of the:articulartacessss sem wees ee ee eee 0, 069 OBtheshattaee ee ae eae cae ee oe Seleeicswa\eas Scceecuinclicisecsseeee ne Seine cHeaeeeaee 0.028 Diameter of the head of the tibia: GLEALCS biecee serene eter alate an et eee ee ee Selene aC om cco cose s ene See ee eee 0, 102 Norevangsiit--ecce cooscaio seh since sceiic eases cose sees Veccees enone Gascnetan ae 0. 096 PUPANSVEISOveneecsea a= eases eee emcees oat earnest cas c so ecicciac aoe e ee 0. 060 Diameter of the shaft of tibia (proximally) : ALEANSVOUSO sre nie seiosma soceneule= same case eee ews ccaneecaekiscceas Sees ee sons 0, 050 MOLE ANON macnn ence ee siti oe cacy oe san eer ne sbeccer se eeteh ce ee 0.045 Diameter of the distal end of the tibia: BET GTR AWS 9588.66 Ses SSUb eS SSSS6 555 SOeS On SoS eee SESS oa SAO OROEAA ciacesSeec--- 0.115 OPO ANG UAL Gress ore apie Sale neem eae hin chew ep teen, uae on) oes dane 0. 060 Remarks.—If ihe bones above described as pertaining to the hind limb are really such, they are smaller as compared with the dorsal vertebra than in Hadrosaurus foulkei, and indicate an animal as large as a horse. 24 >) CIONODON STENOPSIS, Cope. This Dinosaur was discovered by George M. Dawson, of Montreal, geolo- zist of the British North American Boundary Commission, in the Fort Union beds of the Milk River region. It is represented by fragments of maxillary bones, with a few contained pieces of teeth. Probably, several of the numer- ous benes of reptiles of this order, obtained by Mr. Dawson, pertain to the same genus and species; but there are as yet no means by which to distin- guish them from other species of Hadrosauride in the coliection. The maxillaries exhibit the vertical grooves characteristic of the genus, and the teeth are of the rod-like form of those of the C. arctatus, Cope, and the roots are similarly compressed. An important difference in the teeth is seen in their lack of the carina on the enamel-face of the base of the crown at least ; the apices being in each case broken away. Accordingly, the root exhibits no corresponding groove on its inner side, as is the case in C. arcta- tus. The form of the maxillary bone is also characteristic. In C. arctatus, this piece bears a longitudinal protuberance on its inner side so as to have given the face great proportionate width. In C. stenopsis, this protuberance is much less pronounced; the inner face, instead of being.nearly horizontal above, is curved abruptly downward, and a shallow horizontal face of no great width replaces the wide oblique cornice which extends from the alveolar border in C. arctatus. The remains indicate a species of the size of C. arc- tatus. Measurements. s M. Depth of the maxillary bone on a dental groove ......-.---- .---+----------+----+ --2 22+ +22 +e 0. 0350 Diameteriof the maxillary, bonevexternal’ tolalweolij= sss. 22sec semiaa ses le eels ee ee ses eee 0. 0200 Diameteriot a tootheee---- <4 oc ET EOE A Bea ean al eye ae ee oe ea PRE EY 2 en ye a a te 0. 0045 POLYONAX, Cope. Char. gen.—A species considerably larger than the last, represented by vertebree and numerous fragments of limb-bones. The most characteris- tic of the former are two, probably from the posterior dorsal region, which are somewhat distorted by pressure. The more anterior is shorter than the other, and exhibits both articular faces slightly concave; the one more so than the other. They are higher than wide, and the border is scolloped above for the capitular articulation for the rib. There are numerous nutritious fora- mina, and some ligamentous pits on the articular surfaces. The inferior face is rounded. In the longer vertebra, both faces are more strongly con- 64 cave, and at each end of the lower side there is an obtuse hypapophysial tuberosity. The sides of the centra of both vertebrae are concave. The neural canals are relatively small, and the neurapophyses co-ossified. A third vertebra, without arches, is similar in specific gravity, though without the white surface-layer of the others. It is appropriate in size and form to this species, and is peculiar in its flat form, resembling the anterior dorsals of Ha- drosaurus. In this respect, it is related to the shorter vertebra of the two above described as the latter is to the longer. The surface of the posterior articular face is damaged. It was not concave, and is now slightly convex. The anterior is preserved, and is concave. PoLYONAX MoRTUARIUS, Cope. The articular faces are deeper than wide in the vertebrae; the sides are smooth ; the lower face is narrowed and probably keeled. Measurements. M. Anterior dorsal : Length of the centrum ......---..----- SO OHSE 2005 DOSS RSSDOS SaDoSé GSOSR HaSdSOSseo OSeSRS 0. 048 Mlevationitonthemeuralicanalieapesseeerecatescaissenine seis seaiseeetee nee e eee eee eee 0, 094 IWAGtDI S22 237 5 ates Lee es aioe mote tet ee Bae an a en Se ee a ee er ee re ae 0. 094 Median dorsal: Length of the centrum .----. SBIR OAS SEES COS SSC SUSbISE Boao tEbrod SoueSebosoce sese.cseo Hose 0. 057 HMlevationitothemenuralicanalleecse-mejeessee ee eles a eseee ee eee cease eee ee qneeee 0.117 WH bys soe cicais a cia'eie cin cs ateue isle ms evamininleiehe attereladeeelaatelinciejeee rote tersleme cymes one ete terete 0. 083 Posterior dorsal : EVAN OST NEM ne aos Ano aes oS2 545055 See aE Osod SSonSscoeSbe casescesse aces 0. 092 Mle vations. sc; dass acai ce s cacin nem wie eiseecaee ns acmennetenisesuleceutens ca, & =e eeeseemeeens 0.104 Wid thse sa occ ecw pocieeew eee nse tetas once lassen cee caceincen aes Seen eee eneteees 0. 083 Diameter of theineuralennals oo .nc.cesews ccs ones ceimasuicie ce scisees Senn eee Renee ee eee 0. 016 The measurement of the neural canal is made near the base of the neura- pophyses, and is probably a little affected by pressure. The limb-bones embrace portions of tibia, fibula, and some others not yet determined. The portion of tibia is from the base of the cnemial crest, so that one extremity is trilobate, the other transverse-oval. The former outline indicates two posterior tuberosities. The bone is solid, and the superficial layer for 3"" or less, is so dense and glistening as to resemble cementum. Portions referred to fibule have a subcrescentic section, with narrowed width in one direction. Two fragments of shafts of long bones I cannot determine, but they may belong to the pelvis. They belong to opposite . sides; each is oval in section, and the diameter regularly contracts to one end. One side is slightly convex in both directions; the other is less con- 65 vex transversely and gently convex longitudinally. A peculiarity consists of a central cavity present in both at the fractured large end, which is bordered by a layer of dense bone like the outside. Measurements. M. Transverse diameter of the tibia-fragment below the cnemial crest. .....--.---.---..----.------ 0. 125 Autero-posterior diameter of the tibia-fragment at the base of the crest...---...---.-.----.------ 0.095 Widthiof thetiracmentiotmtheytib wl agecemsarsaans else eae eet ese a aieeeiaeeise acer aa aee 0. 073 Dhickness(oLftheracmentiot theyll aememeteeaetse een lereisce tassel aes sae aoe le eee) nero 0. 035 Length of the fragment of an’ unknowupelvicibone-- 2-3. 3-2-2. 2-2... ----e ene oo --- 0.145 Proximal diameterof the fragment of the unknown bone ........-.---..----- ---------2-- ----- 0. 088 Distal diameter of the fragment of the unknown bone.....-.. ....-.----------. eeeee- 22 eee =e 0. 065 The above measurements indicate a much larger animal than the Ciono- don arctatus, and are not very different in size from the Lelaps aquilunguis. ORNITHOSAURIA. As compared with the European Cretaceous, the corresponding beds in North America have yielded but few species. These are of the largest size to which species of the order are known to attain. To Professor Owen and H. von Meyer, science is indebted for the first explanations of the structure of these remarkable reptiles; while Prof. H. G. Seeley, of Cambridge, En- gland, has added greatly fo the work commenced by the elder authors, and also extended our knowledge of the genera and species. PTERODACTYLUS, Cuv. PTERODACTYLUS UMBRosUS, Cope. Represented by the distal portion (ten inches) of the wing-finger meta- carpal; the proximal portion (eight inches) of the first phalange of the same digit, with a lateral carpal, and two phalanges of claw-bearing digits. The distal condyles of the first-named bone are separated by the usual deep groove above and below, and wind spirally to their terminations on the inferior face. The narrow base which supports the inner condyle is bounded posteriorly by an acute edge; directly outside of the base of this ridge is a deep groove or foramen, which is bounded next the external condyle by another ridge, which rises to the base of the inner condyle on the trochlear side. The transverse diameter of the condyles is 0".043, or 17 lines. The proximal end of the first phalange is perfect, but flattened by press- ure. It presents the two usual cotyloid cavities well separated by an ele- 9¢ i 66 vated ridge. Anteriorly, it presents an elevated crest for muscular insertion. This terminates abruptly, and is followed distally by a deep notch. Distal to this is another prominence of the bone, also probably an insertion. Antero- posterior diameter (flattened), 24 lines. The lateral carpal is short and wide; both its articulations are simple and concave. Both outlines are keeled; one very strongly at one end, and at the cther presenting beyond the articular surface for the distal carpal, a wide prolonged process for muscular insertion. Length of carpal without proc- ess, 13 lines; process, 4 lines; diameter, widest extremity, 11 lines. This indicates a very stout carpus. The phalange is penultimate, and is remark- able for its small size, perhaps indicating an external rudimental digit. Tt is only supposed to belong to the anterior limb from its having been found with the preceding bones. It is slender, and has a convex distal articulation, divided by a trochlear groove, and the concave proximal one in like manner divided by a trochlear carina. Length, 9 lines; proximal depth, 3 lines. '‘l his species is the largest Pterodactyle as yet known from our continent; the end of the wing-metacarpal exceeding in diameter that of the species described by Professor Marsh from the same region by more than four milli- meters. From near Butte Creek, Kansas, from the yellow chalk. PTERODACTYLUS OCCIDENTALIS, Marsh. Established on wing-metacarpals and phalanges of three individuals. The articular extremities indicate a species from one-half to two-thirds the size of the last-named. Those of the metacarpal are very prominent above as well as below, and there is no distinct ridge in the trochlear groove between them. The inner condyle does not stand on a base with an acute posterior ridge, but overhangs a rather obtusely-edged support. There is no second ridge on the outer (trochlear) side of it. The same condyle termi- nates abruptly posteriorly on the superior face of the shaft. Width of con- dyle in No. 1, 11 lines; in No. 2, 13 lines; vertical diameter, inner condyle. No. 1, 11 lines; transverse diameter of the shaft above, 8 lines. The proximal articular surfaces of the proximal wing-phalanges are deeply concave: the inner protected by an elevated margin behind; that of tle outer much lower. They are separated chiefly by a deep emargination but on their short adjacent portions by a low ridge. The process for liga- 67 mentous insertion is well developed. The distal extremity is slightly widened, and its articular surface is wedge-shaped with very convex base. Its surface is slightly concave in both directions, and without median ridge. The margin of the shaft terminates in a short tuberosity bearing articular surface. Transverse diameter, 16 lines; length of shaft preserved, but in- complete, 9 inches 1 line. This is possibly the species originally described by Marsh as P. owenzz, a name which could not be used on account of its pre-occupation for another species from England. It was described by the writer in 1872 under the name of P. harpyia; but, a fire occurring in the establishment printing the — paper, its publication was delayed until two days after Professor Marsh had republished his species as P. occzdentalis. The type-specimens of the two species described were procured from the bluffs of Butte Creek south of Fort Wallace, Western Kansas. OrpEr I—CROCODILIA. Only two species of this order are known from the Cretaceous formations west of the Missouri River: the one from the lead-colored stratum of the Benton epoch, or No. 2, in Kansas; the other from the Fort Union group, or No. 6, of Colorado. The latter is a short-headed species, allied to, and near the size of, the alligator of Louisiana. The former is a Hyposaurus, of eight or ten feet in length, found in digging a well at Brookville, and presented to me by my friend Dr. William E. Webb, of Topeka. The individual discovered was not fully grown, but indicates a smaller and stouter crocodile than the £7. rogersit, Owen, of the New Jersey greensand. This genus belongs to the group with subbiconcave vertebra, and had a long, subcylindric snout. HYPOSAURUS, Owen. Hyposaurus vessi, Cope. An anterior cervical vertebra presents the following characteristics. It is that one in which the parapophysis occupies a position opposite the lower third of the vertical diameter. Its centrum is stout in form; the articular faces but little concave; the posterior a little more so than the anterior. The ante- rior is almost regularly hexagonal; the posterior subround, a little deeper than wide. The inferior surface possesses a strong, obtuse, median carina, which 68 disappears in front of the posterior margin. Anteriorly, if, terminates in a short, obtuse hypapophysis. The suture of the neural arch is very coarse. Surface of the bone smooth. Measurements. sp LOT GIN OF TNO COMRWHN seen asosho comcae caod 6e-aNSh SobeEd coB6Ke seOboo So bocustbassSco Sacdsb.cse5 0. 037 Diameter of the centrum anteriorly : WERE ec oacs cSpans ssoans S960 SSc005 Hab Raod0sCaRs GoDSsa noSbaD S6tH6d SobaEa soosEe COSCGe 0. 032 TRIO MVA NE 36365 Ganaco shee ue DSO bR0 OSD OHT DEHOOS dHa6 OS55 BASSEO DS EShS ObOCCd Gob6 becD caseoe 0. 031 Diameter of the centrum posteriorly : \WGHHIGAN BGs Snecao mean oscecesebeso bUdESH DdOctogEne HebeSs Bead coeE Oo GasaSadeocaae Soanes 0. 032 Horizonbaltaemociesseesjisesecisa se eelsemee cies eeeslosaaleace setae e eee ee eee ee eee eee 0. 031 engthtotathe;surfaceror theparapophysisjesssese-2-s oe oes eeae ee ceee eee ete eee eee 0.015 As compared with the HZ. rogersii of the New Jersey Cretaceous, this vertebra is shorter and stouter, and the extremities less concave ; the suture for the neural spine is much coarser. This crocodile was discovered in a bluish stratum, encountered in digging a well in Brookville, Kansas.?| This point is considerably east of the expos- ure of Cretaceous rocks seen near Forts Hays and Wallace. It was the first of the Crocodilia found between the Tertiaries of the Rocky Mountains and the Cretaceous of New Jersey. It was given me by my friend Dr. William E. Webb, of Topeka, to whom science is also indebted for the Polycotylus latipinnis. I have dedicated this species to him. BOTTOSAURUS, Agass. Cope, Proceedings of the American Philosophical Society for 1871, 48. Botrosaurts PERRUGOSUS, Cope. Represented by numerous fragments, with vertebrze and portions of skull, which accompanied the dinosaurian and turtle remains from Eastern Colorado, already alluded to. A portion of the left dentary-bone, containing alveoli for ten teeth, shows that this species is not a gavial. The dental series passes in a curve from the inner to the outer sides of the bone; one or two alveoli behind being probably bounded on the imer side by the splenial only, as in B. macrorhynchus, when that bone is in place. The dentary is compressed at this point ; in front, it is depressed. There is a slight difference in the sizes of the alveoli, but not such as is usual in Tertiary crocodiles. The external face of the bone exhib- ‘This stratum is similar to that in which Dr. Hayden found the fish Apsopelix sauriformis a+ Bunker Hill. 69 its deep pits in longitudinal lines. The angle of the mandible is depressed. The cotylus of articulation is partially concealed on the 6uter side by the ele- vation of the surangular, whose upper border is parallel with the inferior margin of the ramus for two inches to where it is broken off. The outer face of this region is marked by irregular coarse ridges, more or less inosculating, separated by deep pits. The lower posterior half of the angular bone is smooth. A posterior dorsal or lumbar vertebra has a depressed cordate articular cup. The zygapophyses are large and widely spread, and strengthened by obtuse ridges running from the base of the neural spine to the posterior margin of the anterior, and the posterior outer angle of the posterior. One pit at basis of neural spine in front; two before. Ball prominent: sides of centrum concave. Measurements. Lergth of a fragment of the ramus VGA TW TERM Ros coc sa cteS6e sacueU sogOsS'S000 SEDadede6ed 5500 ondond cobaSh Sedo teHe GoSG ons5 H5Ee ID EWN LIMIT! <6 S4S500 005686 bonboo ooEdSe CoeN SSOUSS eSoDed conn HoSH SenSBD Had poEbeo ER oSHe seoCeS IDG HN OF Creat MhyEOM oSoseo so edastooacos sasooo.cedbG6 cdbo50 6600 SuceHE noo 66u8 Beun DaoEes BooSee WiameteroLrthesarcestralvyeolusistemeectesmateee esos see siasmeo eee eae alee ceitee ee iaeeisseiseyaeee = IDTeraiGie OF Wine SMV; co escboo coerce bebe coco dude ss65 SocenS Soda EdSD CboodO HeceSe ee Sods Sets Whidthrofetheibaseofstheranglevof therumuUserceeleceiemieciciassiaeselssacseaieinosecesaae oes eae 0. 048 Depth at surangular..-...+...--.-..---.. SS0Sd oNSd ooNY BEESNS GoDomE DaDtSs cocoHO eésudooEESE eses 0. 03: Mena thyotauiercentrunmsombhenverteblrageesepecccee cscs sciee ce eee ce eeceeceieeeclsanciseiniseseiecee 0. 045 Widthrofstheyarticnlamcupiee ssc sceenseene cee elses lseinisoniaines Acisssisis em nine elses cei ie seleeee 0. 03 Werticalidiameterofihearicul an cup masse ssersecscienctice cee see eiacee ieee sieeerie= see eee eee 0. 025 Werticalidiameterofethemeuralvarcheresscaciessetsecice see cieeeeeeceissee cel ese eee seoee eee se 0. 011 Hxpanse of pheanterionz yrs pophyses\- sels ecrenc\e\elssaiees Nesnisios eas meets) sees ee eelecceees sis 0056 The specimen is adult, and indicates an animal about the size of the alli- gator of the Southern States. Its reference to the present genus is provisional only. SAUROPTERYGIA. As compared with the European and New Zealand Cretaceous beds, those of our country have yielded but few remains of reptiles of this order. Four only areeembraced in the present work, three of which are from No. 3, and one from No. 6. The structure of the scapular arch in Polycotylus is yet unknown ; in Elasmosaurus, it is quite distinct from that of Plesiosaurus, so much so as to have induced me to regard it as type of a distinct family, the Ldasmosauride, characterized by the absence of distinct mesosternal bone. Professor Seeley has since more fully defined this group, and has discovered several species of 70 it in the English formations, some of which he refers to three additional genera, under the names of Cymbosaurus, Eretmosaurus, and Murenosaurus. Allied species, including a Polycotylus, have also been described by Mr. Hector, from corresponding strata in New Zealand. POLYCOTYLUS, Cope. This genus is established on a series of vertebrae, with portions of pelvic arch and posterior extremity, discovered in the upper Cretaceous of Kansas by W. E. Webb, superintendent of the land office in Topeka, Kansas. The point at which the remains were found is about five miles west of Fort Wallace, on the plains near Smoky Hill River, Kansas, in a yellow Cretaceous limestone. There are wholes or portions of twenty-one vertebrae, of which but two retain their neural arches, and six are represented by neural arches only. Four centra may be referred to the caudal series, the remainder to the dorsal; only two indicate the characters of the cervical vertebrae. All of these vertebre, except the distal caudals, are remarkable for their short antero-posterior diame- ter, and deeply concave, articular faces. This concavity is not, however, of an open, conic form, as in Ichthyosaurus, but is flattened at the fundus, thus exhibiting a small, slightly disciform area. The usual pair of venous foramina appears on the under side of the centrum. The neural arch is continuous with the latter, and exhibits no trace of connecting suture. The diapophyses arise from the neural arch in all the dorsals; they are compressed and verti- cal in section. The arch is, of course, narrow antero-posteriorly, and presents a pair of moderately prominent zygapophyses in each direction; the posterior, as usual, articulating downward, the anterior upward. On some of the verte- bree they become closely approximated. The neural spines are narrow antero- posteriorly, and much stouter transversely than in L/asmosaurus ; they are strongly grooved at the base, both anteriorly, and most so posteriorly. The caudal vertebre are anteriorly quite as large as the dorsals. Two anterior caudals present, on the latero-inferior part of the posterior margin, a pair of widely-separated articular surfaces for chevron-bones. A portion of one of the latter remains; it is narrow and subcylindric at the base. The diapophyses are situated on the upper part of the centrum, and are continuous with it, and without trace of suture. There are two distal cervicals, which are much smaller than the preceding. They are solidly codssified, and have been broken from one anterior to them, with which they have been also anchy- losed. Processes in the position of the diapophyses bave disappeared, while a strong infero-lateral process projects from the middle of each, similar in position to the parapophyses (or whatever they may be) of the E/asmosaurus. These processes are decurved, and much thickened and rugose; they may be described as more or less elongate-conic. The neural canal of these vertebree is well-marked, though small. The codssification of cervical vertebrae 1 @ remarkable character, and very unusual. It does not seem probable that these specimens represent a diseased condition, since they are symmetrical, and the inferior surfaces and foramina are unaffected. The rugosity is much that of a ligamentous articulation. Their size indicates a remarkably slender neck, even more so than in Pleszosaurus. That the portions of an extremity alluded to belong to the posterior is rendered probable by the presence of part of an ilium, and by the fact that the portions of the vertebral column secured are chiefly median and posterior. The fragments consist of the extremity of the femur, the tibia, several tarsal hones, and numerous phalanges. The whole limb is of great size compared with the vertebral column, and indieates powerful natatory capacity in its possessor. What the relative length of the femur may be cannot be ascer- tained, as the proximal portion is wanting; but, if it were like the tibia, it was characterized by stoutness rather than by length. ‘The portion remaining is flattened, and presents distally two distinct articular faces for ulna and radius, instead of the uniformly convex outline characteristic of most of the species of Plesiosaurus. The tibia is pentagonal, broader than long, and emarginate externally: The fibula is not preserved. One of the tarsal bones is a flat, unequally hexagonal disk, of less thickness than the tibia and the tarsals, which appear with three faces of broad, plane articulations, and the outer edge rounded in section. Another tarsal or metatarsal is a parallelopipedon, except that one extremity presents two faces meeting at a right angle. Another is similar, but oblique, 2. e., rhombic in section; one of the longitudinal angles is also prolonged. Of the phalanges, there are individuals from three series. Portions of flat bones, perhaps belonging to the pelvic arch, indicate, as do all the other pieces, that the bony structure in Polycotylus is more massive than in E/as- mosaurus, if the only known species has not attained such huge dimensions as 72 some of the latter. These fragments do not throw much light on the structure of the pelvic arch. The structure of the bones is, like that in the order generally, of the coarsest description. There are no medullary cavities, but the cancellous cells are large, and extend everywhere in the direction of the axis of each bone The characters which separate this genus from Plesiosaurus may be derived from the preceding, as follows : First. The deeply biconcave and very short vertebral centra. Second. The tibia broader than long, resembling that of Ichthyosaurus. Third. The coalescence and depression of the cervicals. Fourth. The continuity of the neural arches. | Fifth. The continuity of the diapophyses of the caudals with the centra. The only genus with which this one may be here compared is the Thaw- matosaurus of Meyer. This is known by but a few fragments, and of these but few are present in the Kansas animal. The character on which I rely at present to distinguish them is the much less coneavity of the dorsal vertebrae in Thaumatosaurus. This is, however, not entirely satisfactory. 7. oélithicus, Meyer, is from the Lower Odlite of South Germany. The bones of the specimens of Polycotylus are thoroughly mineralized, and the adherent matrix is a light-yellow chalky limestone, similar to that which yielded the fine fragments of the Liodon proriger. PoLycorTyLUs LATIPINNIS, Cope. The anterior dorsal vertebrae have the centra slightly compressed or ver- tically oval, while the posterior are more rounded. The anterior caudals appear to have been round, or nearly so; they are somewhat distorted by pressure. The sides of the centrum are slightly concave in the longitudinal direction ; below, there is no carina, but at least two venous foramina. There is another large foramen on the side of the centrum, usually not far from the neural arch; there are usually other smaller foramina below this. The bases of the diapophyses are longitudinally grooved behind, sind separate a concavity of the arch in front of them from one behind. In the most nearly median, the most elevated diapophyses stand about equally on the neurapopliysis and the neural spine above it. The diapophyses are vertically compressed, and the cos- tal articulation of the only one preserved is in the same plane. The margins of the external surfaces are not coarsely striate, as in many Sauropterygia. The 73 venous foramina of the distal co-ossified cervicals are in pairs, and of large size. In the proximal caudals, the diapophyses are above the middle of the sides of the centra. In one, the basis of a chevron is preserved. It is cylindric and striate. The zygapophysis on the hinder aspect of a dorsal has a disciform articular surface directed outward and downward; the prominence of its upper face is continuous with the lateral ridge of the neural spine. The anterior up-looking surface is equally small and little divergent. Measurements. Inches. Mens throfatwolcoussiiedicenmicalsressoeesteceiesceseesa saaeeee ce ceceeee ae eee are eects 2.5 Wid thyofs thevanteriorinpon tee eece sacra eee eiece seetsciee eee peter seeeeeeeiee serene ae 1.7 IDE NUNOE WHE Hiner whe) STROM; ccosos cseouG sceceacaKsce enpsooeDSGKe bono posSSo SooSOECHSoSDOsSES 0.9 Verticalidiameteriof thecentrum)of- theidorsal 2) -miej-t= «=e eine =e ele eli ele eleine = eles 3. 42 Transverse diameter of thecentrum of the dorsal.--.-- 22. .2- 22. esece nea eae oe ee eee 2.7 Antero-posterior diameter of the centrum of the dorsal (below) ..---....---.---------------2--. 1.85 Vertical diameter of the centrum of the dorsal (posterior)... -- poasesuesouss céene0 cece coos esate 2. 98 Mransversediameteron theicentrumeor the\dorsallessess-ee essere ee) sae clecnice eels == eee 2.9 sRransVyersealamerenotauhomeuralacanalesasesereseen ees cee ese ormeae eee eee eetee cies 0. 86 Longitudinal diameter of the base of the neural spine..---. ..---..----. ------ ---<------+-c--es 1. 22 Longitudinal diameter of the hase of the diapophysis....-.........-.--------2.--+-<----------- 1.2 Length between the extremities of the zygapophyses (dorsal)...--....-------.------+---------- 2. 26 IDEN GE WHS GUO ME WO WE. Ga cosscosUuasodopenibadaus voucon Sooo eaa0 HoEdauOsenen BhesupoE 0. 63 Henethiorthecentrumion theanteriorncaudaleasee seat eee cees ceceeacicee eee cemelnsiceectascelcciee 1.73 Distance between the bases of the chevron-bone (caudal) .....-.-.---- -----------+--+----------- 2.58 It may be observed that the anterior caudals have a nearly round articu- lar extremity ; one of them is a little wider than high, but they are too much distorted to furnish reliable measurements. The portion of the ilium preserved is an extremity. It is flat on one side and convex on the other. The shaft is solid. The articular extremity is oblique in one direction and truncate in the other, which is at right angles to a short, recurved margin, which has been an insertion or articulation; the flat surface is rugose distally. Long diameter of extremity, 2.75 inches; of shaft, 1.9 inches. ‘The articular faces of the extremity of the femur are at an opeu angle with each other, and are strongly concave in transverse section. The femur is here very flat, with narrow margins; it becomes stouter with dimin- ishing width. Distally, the surface is marked by grooves and small foramina. What may be tibia is the basal frustum of a wedge; the articular faces are broad; the outer margin narrowed; the faces slightly concave. The inner margin is shorter than the outer, and the distal part of it presents a broad articular face. Some of the tarsal bones have been already described. There are thirteen metatarsals and phalanges. They are of stout proportions and 10 ¢ 74 are considerably constricted medially. Those of one series are square in section; those of another, transverse; those of a third, transverse, with one edge thinned or acuminate in section. Some of each form are more elongate than others. Measurements. Inches. Widthof the feniur atthe extremity (restored). - -<-- 22. owe a oe clenye nw am mnie steele eee 8. Depthyvofathewtemuratithorextremibya(mediaM))e a= melee =a eee me moet alos ee selec ee tee eaten ee 1.3 Width of the femur four inches from the extremity..-....--.---.--- 22. 2-22. /- eee ooee ene eeee 6. Thicknessiof the femur four inches from'the extremity... ---~ <- <<. -<-- 25 cone ween renee em seisee 1.95 Wil @? Tite cones seSc5= 6SnH6o Goon6d G556 cauaseRSoosos osonee HoSsc0 SonENS HoaGonoScods Sede 3.68 Meno thvofathotibi aces tenn alll ype aimee meee rea elena elem ole nee nlelae nes leaner 2.6 Widthtofithextarsi (tibia) acess ecmccisereenese sas =a eter meee mae tem aes ise seni t ere 2.48 hicknessjopmhesvarsl (Gib1a)) a eeeeiere se soace ceeiemeio serene ane ee sees ieee see eee 1152 eng thot theyparallelopipediphalan gence as stqe = =alomniele=seisse a eie sane eae eee se eeelee aie 1.56 Widthyof the}parallelopiped|phalangerss. asc .se son ae eee een erlaee ee eee eee tise eee eee il, Thickness of the parallelopiped phalange 1.2 Thickness of the depressed phalange.--.-...-.----.--------- : ils iWidthyofetheyd epressed phalanges ses. es meaten eae lane ae aera elo aie sale ele se eee ener 1.4 en rthvot they depressed ih a) en eee reser ye rete tee tea patel alate ala ate eae tee ae 1L® These powerful extremital pieces indicate a body to be propelled of not less than usual proportions. If this be the case, the number of dorsal verte- bree is considerably greater than in the species of this order in general, and approaching more the Ichthyosauri. J do not intend to suggest any affinity between the latter and the present genus, as none exists. What the extent of the cervical vertebrae may have been is uncertain. The caudals have prob- ably been numerous, though not probably so extended as in E/asmosaurus. The size of the species may be approximately estimated from the pro- portions furnished by Owen (Reptiles of the Liassic Formation) in P/esio- saurus rostratus. The skeleton of this species measures 11 feet 8 inches in length, and the dorsal vertebrae are of less vertical and equal transverse diameter compared with those of the present saurian. We may, therefore, suppose that the latter exceeded the former in dimensions. William E. Webb, of Topeka, discovered the specimexs from which this species was first described, and liberally forwarded them to me for examina- tion and description Other specimens have been discovered since that time by various other persons. I have received numerous fragments of an individ- ual of about the size of the one above described, which were found by Prof. B. F. Mudge, at a point near the mouth of the north branch of the Smoky Hill River. These consist of a few vertebrae, portions of pelvic and scapular arches, and three proximal bones of the limbs. Which of these is femur and which 7d humerus, I am unable to determine, owing to their close resemblance. The vertebree do not differ from those of the specimen just described. The limb- bones are stout and expanded, and thinned distally ; this thinning is remark- able, and indicates a much flattened metapodial region. The head is slightly expanded, the articular face being turned obliquely to the inner face of the shaft; the surface is pitted for attachment of the articular cartilage ; two- fifths the length from the proximal end is an extensive and exceedingly rugose surface, as wide as the shaft, for the insertion of the adductor-muscles. Measurements. M. Diameterof thercentrum\of ithelumbar yertebrajna---ceenee se eoeceeee coe erioee ceeees coerce 0.08 Ib eyayein a Ove WA) (1) INMTIE MSooo6do doen seSuanisssaao ddoso0 Geo sonoSnad Sas nabSoo Rn eeasbobosaSsoeas 0.45 Miametervofithevwheadys je srs iare sete ieee isi cise ero sie el eyewe ete a ey elote era iat siete ete loueteleelaiake oe steisiers sae iegomeate 0. 125 Diameter ofethe shatbs. cease ne sae Sears waists ae sere eieteletelia nts osc ae eo ay eale senate ole esleteeis ie; Semmes eats sae 0. 098 Diameter of the distal end (transverse), restored in! part...--- 2.22 2.020-22- -ce- 502 ones eens eons 0.18 Should the humerus have been related to tke fore-limb, as in Plesio- saurus dilichodirus, Conyb., the latter would have had a length of 4 feet 3 inches; as the proportions of the radius and phalanges are shorter, the limb was probably relatively shorter. If related to the total length, as in the same Plesiosaur the humerus would indicate a length of 174 feet. The cer- vical vertebrae become attenuated, as compared with the dorsals, to a greater degree in Polycotylus than in Plesiosaurus. ELASMOSAURUS, Cope. This genus has been more completely preserved to us than any other American representative of the order. In the interpretation, however, con- siderable care is necessary, as the form appears, at first sight, to reverse, to a remarkable degree, the usual proportions of known reptiles. The scapular arch, in the absence of the episternum, presents the same number of ele- ments as the pelvic, and is not without resemblance to the latter, as it exists in some species of the order. The fortunate preservation of the series of cervical vertebrze shows this to have been, in the typical species, three times the length of the body; much exceeding in this disproportion that known to exist in other species of the order. The neural arches are everywhere continuous with the centra, without sign of suture, and are externally plane. The neural canal is exceedingly small for the size of the vertebree, especially on the lumbar and caudal verte- bree. 76 The dorsal vertebra are remarkable from the fact that the diapophyses disappear on the anterior part of the series, and gradually diminish in length from behind forward to the point of disappearance. On the median and posterior parts of the series, they are very elongate, and rise for a short dis- tance from the basis of the neural arch. Anteriorly, they descend and sherten, and finally remain only as the slightly-elevated borders of rib-pits. Through- out the whole of the anterior portion of the column to the cervicals, the neural spines are of great elevation, and of such antero-posterior extent as to be nearly continuous. The cervical vertebre are not only more numerous, but become anteri- orly much smaller and more attenuated than in its allies of the same family. They are remarkably compressed, the centra much longer than deep, and deeper than wide, and with smooth concave sides. The ribs of the anterior cervico-dorsal region are inserted directly in the vertically-oval pits of the centrum. Immediately at the point where these cease, thin traverse processes appear to arise from the lower edges of the rib- pits. They form a continuous series with the ribs, and soon rise from the plane of the lower face of the centrum, and are directed obliquely downward. At the end of the cervical series, they are directed nearly vertically down- ward. The number of these vertebrae is very great; the anterior diminishing to a very small size; the whole measuring a little more than half the total length. Most of the cervicals possess two venous foramina below, the dorsals two, and most of the caudals one. The resemblance of the caudals to the usual type of Plesiosaurus is seen in the fact that each bears near its posterior articular aspect, on the inferior face, a pair of articular surfaces for cheyron-bones. Similar vertebrae had been described by Leidy as the caudals of a genus he called Discosaurus. The study of the present genus shows that they are really of the caudals of the allied genus Cimoliasaurus, the support caudals of the latter being the cervieals. The ribs are simple-headed ; the abdominal ribs seen in Plesiosaurus are possibly wanting, as none were found by the discoverer of the fossil, after a careful search. The end of the muzzle, with symphysis mandibuli, was preserved. This is flat, the sympnysis co-osified and rather short, the premaxillary grooved at the imtervals between the dental alveoli. The teeth are deeply implanted, with small pulp-cavity, are cylindric, and furnished with nearly straight elon- 77 gate conic crowns, which are minutely but sharply striate to the tip; the ridges straight, continuous. There are no indications of nostrils, so that these were probably posterior, and near the orbits, as in Plestosaurus. The pelvic arch is more extended than the scapular, and strongly re- sembles the pelvic arch of the Plestosauride. The scapular arch is peculiar ; the claviculi are broad, flat bones, resembling the pubes of certain tortoises, while the coracoids are much like the coracoids of Plescosaurus. The clav- icles have a greater transverse extent than the latter, and have a very exten- sive line of union medially, and a narrow posterior prolongation, which meets a similar anterior one of the coracoids, separating the intervening foramina. They appear to form about one-third of the walls of the glenoid cavity, and have a constricted base, as in some Plesiosauria, applied to the extremity of the coracoid. The form of the glenoid cavity cannot be readily ascertained from the absence of the scapula. What we have of it would suggest the ex- istence of a fore-limb, of comparatively little power, though no remains of such have been found. The acetabulum is smaller than the glenoid cavity ; this point, with the obvious source of propulsive power in the tail, indicates that the hind limbs were smaller than the fore. There is no trace of sacrum, nor of any modified diapophyses for support of an ilium. The ischia are flat, subtriangular bones, with a long median line of junc- tion, and communicating anteriorly with the posterior prolongation of the pubic plate. Their postero-exterior margins project well backward. The pubes are broad plates, whose anterior margins diverge from each other. They are broader than the ischia, and form a broad, shallow basin for the support of the viscera. The suture defining these elements is obliterated ; they are continuous, and form a weak, inferior keel on the median line. A simple curved ilium has been preserved, for which there appears to be a smooth articular surface on the pubis, to. which it was attached. The acetabular portions of these elements are flattened and furnished with convex articular surfaces. The supposed ilia are short, curved bones, resembling that of Plescosawrus latispinus, Ow., or of some of the other spe- cies of that family. The shank is flattened cylindric; the distal extremity dilated, rounded, and flattened; the proximal extremity subtruncate, or trun- cate in two or three unequal planes, and with a median pit. It fits well when applied to a concavity on the articular surface of the pubis. The ver- 78 tebrae above the pelvic arch were furnished with elongate, subcylindric dia- pophyses. Dr. Turner, the discoverer of the original specimen, having made a sec- ond careful search and renewed excavations at the original locality, failed to find any bones which can be assigned to humerus, ulna, radius, carpus, or phalanges, or similar elements of the hind limbs. The pelvic and scapular arches were further completed, and an additional number of ribs obtained. The glenoid cavities are rather angular, and both were filled with solid argillaceous matrix. The acetabula are not cuplike, but merely exposures of the narrow plane extremities of the pubes and ischia; they were covered with thin layers of gypsum; the pieces of the ilia were found imbedded in the mass of matrix which occupied the pelvic arch. This genus is well distinguished from Plesiosaurus by the peculiarity of the scapular arch. The mesosternum appears to be wanting, and the clay- icles and coracoids form a breastplate. If the claviculus was ever united with the scapula, as in Plesiosaurus, no evidence of it can be seen in the speci- men ; it is also broader and more extended anteriorly. Differences from other Sauropterygia—The only genus which it is nec- essary to compare with the present one is Cimoliasaurus. The following may be noted as generic distinctions: the series of cervicals rapidly diminishes in Cimoliasaurus in absolute size and in relative length of the vertebrae, which are not compressed. In the present genus, they maintain a similar and in- creased length for a considerable distance, diminish in length very gradually, and are much compressed. The diapophyses of the dorsal vertebra, as they descend in Cimoliasaurus, continue well developed until they attain the infe- rior planes of the centra, and have there a downward direction. In Elasmo- saurus they cease while yet on the middle of the centrum, and are replaced by pits throughout the remainder of the length. The neural canal is everywhere markedly larger in Cimoliasaurus. The American genera of Elasmosauride may be compared as follows: Posterior cervical vertebrae without diapophyses : Cervicals long, compressed; neck very elongate. ---- ~~ - Elasmosaurus. Posterior cervical vertebrae with diapophyses : Cervicals quadrate, short, depressed, transverse, rapidly diminishing in size, hence the neck short.--......-. Cimoliasaurus. 79 Professor Owen figures and describes (Reptiles of the Cretaceous, Pale- ontographical Society) a vertebra which very closely resembles the cervical of Elasmosaurus. Ue considers it to be the cervical of a peculiar Plesiosau- rus, which he calls P. constrictus, remarking, at the same time, its remark- ably inferior pleurapophyses. EXLASMOSAURUS PLATYURUS, Cope. This, after Mosasaurus, the most elongate of the sea-saurians yet discov- ered, is represented by a more than usually complete skeleton in the museum of the Academy of Natural Sciences of Philadelphia. It was found by Dr. Theophilus H. Turner, the physician of the garrison at Fort Wallace, a point situated near the boundary-line between Kansas and Colorado, and a short distance north from the Smoky Hill Fork of the Kansas River. Portions of two vertebre, presented by him to Dr. Leconte when on his geological tour in the interest of the United States Pacific Railroad Company, were brought by the latter gentleman to Philadelphia, and indicated to the writer the exist- ence of an unknown plesiosauroid reptile. Subsequent correspondence with Dr. Turner resulted in his employing a number of men, who engaged in exca- vations, and succeeded in obtaining a large part of the monster. Its vertebrae were found to be almost continuous, except a vacancy of some four feet in the anterior dorsal region. ‘They formed a curved line, a considerable part of whose convexity was visible on the escarpment of a bluff of clay-shale rock, with seams and crystals of gypsum. The bones were all coated with a thin layer of gypsum, and, in some places, their dense layer had been destroyed by conversion into sulphate of lime. The scapular arch was found in large part adhering to the bodies and neural spines of a series of the anterior dorsal vertebree, and was detached from it at the academy. The pelvic arch had been slightly crushed, and the lumbo-sacral vertebrae forced into contact with the ischia, where they remain. A broken extremity of the supposed ilium was forced into the matrix which supports the ischia. Many of the dorsal and caudal vertebree were sent, and remain in continuous masses, so that the succession is readily traced, and the true relations of the extremities preserved. In removing the matrix from beneath the vertebrae, scales and teeth of some six species of Physoelyst and Physostomus fishes were found, including an Enchodus and a Phasganodus; the latter indicating a new species, which I 80 have called P. carinatus. These animals had doubtless been the food of the Elasmosaurus. The end of the muzzle was broken from a part or whole of the cranium, which has not been rediscovered, though Dr. Turner has made careful search. It was found in front of the vertebree, here regarded as cervical, at some dis- tance from them. The whole skeleton has been under considerable pressure, so that most of the ribs have been pressed flat on the vertebrae; the long parapophyses of the cervicals have most of them been fractured at their bases and compressed, those of opposite sides thus approaching more nearly in the form of chevron- bones than they otherwise would have done. The proximal cervicals are obliquely flattened by the pressure; the other cervicals have the bodies natu- rally flat, with the articular surfaces much less so than the median portion. Some of the caudals are obliquely distorted. Description— Vertebre.—TVhe neck may be safely assumed as a point of departure, as it consists of above sixty mostly continuous vertebrae, which graduate to an atlas of very slender proportions. Most of them preserve more or less developed parapophyses. At the posterior extremity of this: series sixteen are perfectly continuous, and in this portion a great gradation in form is apparent. The anterior are narrow, compressed, and similar to the more distal cervicals in the elevated position of the lateral angle; the anterior are subquadrate, thick, and with lower lateral rib, and stronger (?) pleurapophy- sis. In these respects, the latter resemble the dorsals which follow toward what I believe to be the tail. Four anterior dorsals are in one mass (figured in Plate 3); in this series, the lateral angle first approaching is finally lost in the margin of the rib-pit, the posterior thus resembling other dorsals. In a series of four anterior dorsals, which, like the preceding, are in their original continuous mass, those of one extremity have centra rounded in section, with inferior rib-pits; those of the other have quadrate centra and elevated diapophyses; the former have the character of the first dorsals, the latter of the median dorsals. The posterior dorsals and anterior caudals form, in like manner, a continuous series of eleven vertebree, fractured in four places. In them, the diapophyses steadily descend, reaching the inferior plane in the last; thus, with the reduction of the venous foramina to one at the seventh, indicating the point of transition from dorsal to caudal series. The zygapo- physes preserve the usual arrangement, but are much compressed, so that the 81 posterior or down-looking are confluent, and scarcely separated by an emar- gination. The neural spines, at their bases, have a slight posterior obliquity; and the superior portions lean strongly in the anterior direction. The inferior limbs of the cervical pleurapophyses appear to be entirely wanting. The articular faces for the chevron-bones are seen at the extremity of the inferior rib of the caudal. ; Of the cervicals, there are both axis and atlas. Of the caudal series, probably the distal half, at least, is lost. A single vertebra near the middle does not relate to either of those anterior or posterior to it. ‘There are, there- fore, at least four lost from that region also. There is a considerable interruption immediately anterior to the last dorsal vertebra. Three large vertebrae, with long diapophyses belonging here, were embedded in the hard matrix which protected the pelvic arch. These are far from relating immediately to the vertebrae preserved before and behind them. I estimate the number missing as follows: Seven of the four- teen dorsals preserved have more or less elongate diapophyses. In Plesio- auri, vertebree of this character are much more numerous; in P. homalospon- dylus, Owen gives seventeen. If we add ten to the series in the present species, it will give the abdominal space between the adjacent margins of the oo. pubis and coracoidea an extent equal to the length of the pelvic arch. This is relatively shorter than in the Plestosauri. Dy. Turner found that a space of ‘three or four” feet intervened between the two portions of the skeleton, which was otherwise continuous. I think ten an average number to represent safely the missing dorsals. From the cervical proximal regions, probably three vertebrae are missin gg from two interruptions. The remainder of the cervical series exhibits three interruptions. Most of the proximals have been broken medially, leaving the articulations solid, an advantage in determining their continuity. Three vertebrae and one-half are thus found missing in this region. The whole number of vertebrae preserved and lost, with the relative lengths of each, may be stated as follows: lle 1 | Present. Lost. Total lengths. No. | Length. | No. | Length. Inches. Tuches. Inches. @ramlom rs oa cee oscars hee daw ce seb enides cess coded osealleennes |Seeses Sere Comer 24, 24. OBRmGHicsccoce bensbe Sonend ppaasu eoSuoNsess Bons so6eseu5 G24 257.5 34 22.3 279. & IDOrSO-)UMPATS Hae see ae ee ee eee cee ania eieieraae taal Hoi 0) | 0 37.6 92.16 @andalss oo. accrue Seciiseee.= pe aera his eS spears cic Steg 2] 60.4 30 60. 120.4 Ob ali aoe see eae era ee ae Se eros teens ra) 1034 | eevee ol @AS Ta Eee eecees 516. 36 This gives the total length to the animal of 43 feet 2 inches, which, in- creased by the amount taken up by intervertebral cartilages, will give roundly about forty-five feet. Of this, twenty-two must be reckoned to the neck. The cervical vertebr@ are assumed to commence where the rib-pits cease and the continuous lateral processes commence. This point is ascertained with difficulty on the specimen. It is, however, perhaps the same point where the longitudinal lateral ridge leaves the upper margin of the rib-pit; and it was to the series of vertebrae which pass this point that the scapular bones, the clavicle, and the coracoid were found attached. On the anterior dorsals, the inferior margin of the rib-pit is most prominent, and is finally produced into the flat, thin process which is directed obliquely downward on the cervi- cals. Both these and the posterior ribs are crushed on the centra, and project obliquely below them; their mode of attachment is thus rendered rather ob- scure. A similar structure exists in the posterior cervicals of Cimoliasaurus, while, on the anterior dorsals, short, thick diapophyses support the ribs. The proximal cervicals are remarkable for their compressed and elongate form. They are, for a considerable distance, longer than any dorsals. The lateral longitudinal ridge rises successively nearer to the neural arch and disappears. The articular surfaces are vertically oval, flattened above and below. The inferior faces are slightly grooved in line with the venous foramina. These vertebrae diminish in length, and, in front of the posterior third of the series, materially in depth. They diminish to terminal ones of very small size. In most, the decurved (?)parapophyses are broken near the base; but the basal portion of various lengths generally adheres. They are as wide as a rib and scarcely half as thick. They have much greater antero-posterior extent on the terminal than the proximal cervical centra, having a base five-sixths the length of the latter. The zygapophyses have relatively a larger size on these 85 than any other vertebrae. In such, the centrum is less compressed. though with concave sides, and with a section rather quadrate. The cervical vertebrae, from the sixty-sixth to the thirty-ninth, are all longer than the dorsals; they commence four inches in length, increase to five, and diminish to four again. Measurements. Inches. Line. Meng thvofesixty-third cenyi caliemerr ewer eisteysesespele eles neal reore ate= guesoeD asda cuscbososesadeuc 4° 9.2 Depth of the articular face of the centrum .... ....-....--. J ats Rp AHR RE BAOOUeIOR Gero Sees 3 8. Wadthrofitherarticulacfaceyotathercenthumesieseeea-e ete cee aici eee eect eee 310.2 Motalkelevationtof the minthycenvica lumens meee eee mie seinen e eects tessa este anne Autetior posterior diameter of the third cervical......-.-....-. -----------. ---------+------ 2 2. Pransverse diameterjof the) third cervical —- a. ween serene eosin nies m= = ei leieiele = 2 ills IVETE NO Ptdne Meal GPM) 65-5 Sk53 4sa6 cocdes Gabb cHSou coBEoO cose acuoDSyaN esoce icocboecsaccsads Il Sh2/ Widthvomtheyheadtofenitbereeeereeeeeeeteriacceetes sicsacceicsiescise erie csicine cise ee necniecet 1 3. Widthyvonthe:shattjoferibeeem-eessernresset eerste ea cieciasertiete sistem cise rath eres amelie 1 10.5 Many of the rzbs preserved have been pressed upon the vertebrae and crushed. The first dorsal is that vertebra which first presents a distinct articula- tion for a rib. The diapophyses are never much elevated above the cen- trum, and are longest on the thirteenth (inserting seven supposed to be lost). Their form is stout and much depressed, and distally expanded. They dimin- ish gradually, and, on the third, are represented by a longitudinal angulation ; the superior angle is first distinct on the first, and bounds the articular sur- face last on the third. They give the transverse section of the posterior cer- vicals a pentagonal form; that of the anterior dorsals is nearly circular. The latter are strongly constricted medially, and the articular faces are slightly concave. The external surface near the included angle is coarsely ridged, in conformity with coarse cellular texture of the spongy bone. The venous foramina gradually become more widely separated, approaching each other again on the posterior cervicals. On the dorsals, they occupy the bottom of a more or less pronounced concavity. ‘These concavities, on the posterior dor- sals, are bounded externally by a strong obtuse longitudinal angulation, giving a quadrate outline to the section of the centrum in this part of the series. The posterior cervicals are not readily distinguished from the anterior dorsals. In the latter, the ribs appear to be present, of reduced length, judg- ing from the smaller size of the remaining heads. The articular pits continue to descend till their lower marginal ridge is the inferior lateral angle of the vertebra. On such vertebre, the inferior surface is flat. 84 Measurements. f Inches. Lines. Antero-posterior diameter of the (?) twelfth dorsal ...-.......-..--..----2- +--+ ----e--s ------ 3 2 Transverse diameter otmerarbicular surface s-----s- -osjcce ene ces cane sacieeereeeie PONS SF tee ean 4 10. Verticalidiameteriotetherarticnlarsurtace-c.- secs e--) sae) oeeal ee aee ee eo eee ee eeeee A D155 Neuralicanalfand spine) (the lattembroken))-.-- ssssccs esos sees oe eaten clea eee eee eee & Sh5 Length of the diapophysis of the twelfth dorsal........ .---.- .----.- 2200 cece se eoee eeeeee ooo 4 Widthyofthesdiapophysisat thepmiddley eee — ye cien «<= neo) me eel ain ele eee ieee eel al Os Antero-posterior diameter, of the (?) eleventh dorsal ---. .----.- 5-25. ooo ee owe eee ceceice ae 3) 485 ‘Transverse posterior diameter of the articular face ..-........----..----2 -.---- ---- -e-- -o- = 5) Gh Vertical! posterior diameter of the articular face. --- ------- -- --- = oe eae cone ene ace owen eee 3 10. Transverse posterior diameter of the neural canal ..........----.---.---------- eensesecaese 10.2 Transverse posterior diameter of the articular face of the third dorsal......-...-.--..---.----. 5 2.5 Elevation of the centrum, arch and spine of the second dorsal ..--..-...--..-.----.---------- 1 19: Elevation of the upper edge of the zygapophysis of the second dorsal.......-.---------------- 6 Length of the zygapophysis at the upper edge of the second dorsal..--..-...-+..--------- eee) Lal ONS ienethionthecentramyofsthelasticervicalenn seems sel=s/eteee eee ete eo ete eee eee eee 4 Width of the centrum of the articular face of the cervical.--..----. .----.------2----< «---+=-- Ss Elevation of the neural arch and spine of the Gervical..-.--..--.--- BERS coo ance Seiad Gcieaes “es Antero-posterior width of the neural spine of the cervical at the zygapophysis -.------..----- 3 Gh The caudal vertebre have slightly concave articular surfaces, which are not bounded by groove or ridge. The neural arches have flat sides; and there is no longitudinal ridge above the diapophyses. The neural spines are ele- vated; the margins of those of the adjacent vertebrae close together. The diapophysis is very short and wide, terminating in a large oval concavity for the pleurapophyses. [ach limb of the chevron-bone is attached to an articu- lar surface on the lower posterior face of the vertebra at the extremity of a strong inferior ridge. These inferior ridges are rather close together, and distinguish the vertebrae from those of Cimoliasaurus magnus, where they are wanting. They are absent on the anterior seven of the caudal series. The diapophysis is nearer the anterior than the posterior face of the vertebra. The venous foramen is single and median on all but the last six caudals. Measurements. Inches. Lines. Antero-posterior diameter of the fourth candal-_--.-<--2 -- 32.) S22 oo sees cnee eat eee eee ee 2 4. Transverse posterior diameter of the fourth candal.-.....--. 2 bo. ccce coon ees eee een eeee 310.5 Totalielevation of the fourth caudal-.------------ --=- 22> See ee ee eS Vertical diameter of the centrum of the fourth caudal......-...........-..--------.--- asees 3 1.5 Antero-posterior diameter of the diapophysial pit ....---- 2-2 22-2 -- ss ees eee eee eee een te Henrthiofthe ninthicaudal fo 322 5.0 us. cel feck as Led isn Je eke eee eine ieee ae eee eS) Transyerseidiameter of the articular face .---.--.=---- -o-ceciee eae sees coe Seer eee Eee Gs Vertical diameter of the/articular face .--- .--<2- --2 2-225 oas2 coc on cone tee se nee Eee ID Par Heads of fourteen ribs are preserved, and a great number of shafts. The heads are simple, with elongate-oval articular face. They are oblique in the narrow direction, and frequently in their length also; the margins are somewhat everted. The extremities of the diapophyses of the larger dorsal vertebree are transverse, some flattened, the others more oval; the more ante- 85 rior are subtriangular; and the rib-pits on the first dorsals are subround or vertically oval. Thus, the heads of the ribs also vary. The shafts are all flat, probably partly from pressure. They are frequently curved in the direc- tion of the compression, which suggests a vertical head. They, however, are probably more or less distorted, and the plane of compression changed. No well-defined distal extremity of a rib can be made out; nor have anything like abdominal ribs been preserved. The scapular arch is remarkable for its large clavicles (or procoracoids). As preserved, the latter are quite convex downward, both antero-posteriorly and transversely ; while the coracoids are equally concave in both directions. The clavicles have a remarkable external flat projection, which is separated from the glenoid cavity by a deep sinus. The glenoid cavity is bounded by an elevated ridge, which sends a branch along the claviculo-coracoid suture to the precoracoid foramen. This foramen is relatively of small size, and is longitudinally oval; the two are separated by an isthmus composed equally of processes of clavicle and coracoid. The coracoids are very thin, except in a transverse portion, which extends across behind the precoracoid foram- ina; a strong elevated rib extends across the posterior face at this point. The outer margin of the coracoid is thickened, rounded, and slightly concave. Measurements. Inches. Lines. Greatest antero-posterior length of the scapular arch...-............-..--...2--- +--+. ---- 33 6 Greatest antero-posterior length of the clavicle -....--.-.----- 12 ---2s2 22 ee ees eee eee 14 9 Greatest antero-posterior length of the glenoid cavity .....-.--..----....--. ---------+----- 6 ¢ Greatest antero-posterior length of the precoracoid cavity .-........-.-.-.-...----.-------- 7 3 Transverse extent of the claviculi).----.-- 2-2-2. .22 2. 2-225. Jeo porS moe Heap RetEce anenasaaed 27 MransyersevextenbOrmbhescoracol dc admeendir eet eee eeeere ee cee eeec seer eee eter aace secs 16 romitheacetabulumstontheltoramenie seer eerie ener eee cian eee ae ee eee eee 7 6 The form of the posterior margin of the coracoidea is unknown, and they are much broken on the inner margin. The greater part of the pelvic arch appears to be preserved. From the obliquity of the median suture, and from the form of the pubes, as they are preserved on a large nodule of indurated clay, it is evident that they have formed a boat-shaped support to the abdominal viscera, with an cbtuse kecl on the median line below. Measurements. Inches. Lines. Greatest antero-posterior length of the pubis and ischium ..............-......--.--..-----. 25 , Greatestjantero-posteronlensthiorshelpulbistesee een iieee sees eieelein ce ele ciden ce Saseunene 13 6 Antero-posterior median length to the notch of the ischia....-.....-..--..-...---.---.--.--. 7 Leng thyof the\coracoidsibehindythemotchiesees eee eee wee eee eee ne eGskeeece cide coer 4 6 Greatest; wid thi ofthe pubes ese rcr tye cere cers irc rie aioe ssc ciocc step ne cus els oes acreciemeis acs 27 6 Greatestiwidthiofthelschiamsecn mec sce e eee eee eee celeron ceases ecw mene eas) o 2D 86 The anterior and lateral portions of the pubes are very thin, as are also the median posterior portions of the ischiadic plates. The pubic bones are thickest on the posterior margin; they present a downward-projecting median convexity near the anterior end. Depth of the articular face, 2 inches 8 lines. The superior surface of this arch was brought to light by the exertions of my friends B. Waterhouse Hawkins and William M. Gabb, who removed a large mass of matrix, which fortunately protected and accompanied it. This presents a transverse thickening extending across it, and continuous with the posterior margin of the clavicles. A median longitudinal thickening extends from this to the anterior emargination, embracing in its angle with the trans- verse a shallow concavity. The posterior projection, which is continuous with the median part of the ischia, is strongly deflexed behind the transverse rib, and is continuous with the basinlike concavity formed by the united pubes. The glenoid surface of the pubes is a sigmoid, while that of the ischia is regularly convex. The articulation of the ilium bas been exclusively with the former. Of the pleurapophysial portion of the two arches nothing appears to be preserved except two lateral symmetrical long bones. One was found em- bedded in the mass carrying the pelvic arch, and they articulate well with the pubes; but the articular extremity is too short to articulate with ischia at the same time. Though they resemble the inferior view of the procoracoids, they represent the ilia of Plesiosaurus. The head is subdiscoid, rather flat, slightly projecting eccentrically with a ligamentous pit. The articular surface is very oblique to the axis of the shaft, and is separated from the surface by a marked angle all round. Nothing like a trochanteric ridge is apparent in this bone. Measurements. Inches. Lines. eng thanitheimidd leohthe Curyessseee == sa) 2 see cena aee nee aeelee ese a es 9 9 Minmeteratthothendi-2s-ssccaec scene cca censs see ciencee cee eas oe ne 3 3 rameter, .distally,Onwhe (CULV Es cesses eee) e ene eee ne a 6 Diameter, distally, straight The shaft is flattened cylindric; much flattened nearest the proximal extremity. The latter is very oblique to the shaft, and slightly convex near the proximal margin. The end of the muzzle preserved includes also the symphysis and parts of the rami of the mandible. The parts have been crushed together, and the 87 ends of the teeth broken off. The alveoli of the two jaws incline at a narrow angle to each other; hence the teeth, which alternate, cross each other near the middles of the crowns. The parts preserved appear to belong to the premaxillary bone, theugh no suture can be found, and the bony walls are so thin as to render their obliteration a probability. There is a keeled ridge along the middle line above, which is not continued to the margin of the bone. The form of the muzzle is narrow; the sides subparallel near the tip, which is elongate rounded. The mandibular symphysis, however, is not very elon- gate, as the rami are given off at three inches from the tip. The latter ap- pear to have been quite slender from the various small sections or pieces sent with the muzzle. The premaxillary border of 4 inches 7 lines exhibits eight teeth, or their alveoli, of which the median two are close together, and not sep- arated by any mandibulars. The sections of the teeth are round or oval, and their sizes are irregular, probably on account of differing age and degree of protrusion. The diameters at alveolar margin vary from 6 lines to3. Their form is slender conic, or, with the root, slender fusiform, and the pulp-cavity is small and median, sometimes cylindric, and sometimes narrowed. ‘The surface, from a short distance above the alveolar margin to the tip, is marked with acute, threadlike ridges, which are sometimes interrupted, and sometimes furnished with short branchlets. They are more or less undulate, and do not unite, but simply cease as the tip of the tooth is approached. The latter is smooth without lateral cutting-edges. The width of the mandible at the commencement of the rami is 3 inches 0.05 line; of the muzzle of the seventh tooth, 3 inches 7.5 lines; at the third tooth, 2 inches 4.2 lines. General Remarks.—The tail is a powerful swimming-organ, more or less compressed in life; hence the specific name, which means flat-tailed. The danger of injury to which such an excessively elongate neck has been exposed would render the recovery of a perfect specimen like the present an unusual accident. The neural spines of the dorsal region are so elevated and closely placed as to allow of little or no vertical motion of the column down- ward; while, those of the cervical and caudal region being narrower, the elevation of the head is quite possible, and an upward flexure easy. The habits of this species, like that of its known allies, were rapacious, as evinced by the numerous caninelike teeth, and the fish-remains taken from beneath its vertebree. The general form of this reptile was that of a serpent, with a relatively shorter, more robust, and more posteriorly-placed 38 body than is characteristic of true serpents, and with two pairs of limbs, or paddles. It progressed by the strokes of its paddles, assisted by its powerful and oarlike tail. The body was steadied by the elevated keel of the median dorsal line, formed by the broad, high, neural spines. The suakelike neck was raised high in the air, or depressed at the will of the animal, now arched swanlike, preparatory to a plunge after a fish, now stretched in repose on the water or deflexed in exploring the depths below. Comparisons—In Cimolasaurus magnus, the dorsals with elevated diapo- physes have considerably larger centra than those in which they are situated lower down. In EL. platyurus, these vertebra are of relatively equal length. The cervical pleurapophyses in C. magnus are anteriorly considerably stouter and less flattened. In comparing this species with the Cimoliasaurus grandis, Leidy, from Arkansas, we observe, first, the generic character of the strong inferior dia- pophyses in the latter. That species marks itself also as a pre-eminently short-necked form, as these anterior dorsals are even shorter than in CL mag- nus, being nearly twice as wide as long. The depth of the articular faces is also relatively greater than in the L. platyurus. Localities—This species has been found in various parts of Kansas, be- sides that from which the specimen above described was procured. Prof. B. F. Mudge obtained vertebrae from a point thirty miles east of Fort Wallace, which probably belong to this animal. PLESIOSAURUS, Conybeare. Two American species have been provisionally referred to this genus: the P. lockwoodii, Cope, from No. 3 of New Jersey; and the P. gulo, Cope, from IXansas. This determination is only temporary. since the structure of the sternum, in which the type-characters of the sauropterygian families are to be observed, are unknown. The two species agree with Plesiosawrus, and differ from Ldasmosaurus and Cimoliasaurus in the non-codssification of the arches and centra of the vertebrae. PLESIOSAURUS GULO, Cope. The typical specimen consists of eleven cervical, thirteen dorsal, and seven or eight other vertebrae, with portions of scapular and pelvic arch and ribs. 89 The cervicals are longer than wide, and considerably compressed in form anteriorly, but depressed posteriorly. This is partly due to pressure, but not wholly ; and it is likely that the posterior centra are about as transverse as in Cimoliasaurus magnus, Leidy; while the anterior are relatively several times as long. In the length, the latter resemble the English Pélesiosauri, in which the centra are also compressed. The compressed anterior centra exhibit a ridge on the side above the middle. A more massive ridge extends between the articular extremities at the lower part of the side, and presents a pit for the parapophysis. The pit for the neural spine is of nearly similar size. Where the cervicals begin to be depressed, two foramina appear near together on the inferior face, and the articular extremities display an open obtuse emargination below. They are also emarginate for the neural canal above, so as to have a form approaching a transverse figure 8. In the large posterior cervicals, the sides are contracted both below and at the sides. In aul the cervicals, the articular faces area little concave; in the larger, with some median conyexities. In none of the dorsals preserved are the diapophyses seen to issue from the centra; hence the former are probably not posterior in position. The centra soon become smaller than those of the posterior cervicals, and are subround in section, with a well-marked emargination for the neural canal. The sides are gently concave, and are without angulation, but are marked near the articular extremity with short, sharp, and regular undivided ridges, eight in a half-inch. The articular faces are slightly concave and without ridges. There are the two inferior foramina, and one on the lower part of each side. The articular face for the neural arch is an oval pit extending the length of the centrum, and interrupted by some transverse ridges near the middle. The vertebrae diminish in size posteriorly. ‘Two centra, probably sacral, resemble the dorsals, but present an extensive vertical articular surface on each side. his facet has raised edges, and terminates above in the longitudinal surface for the neural arch, having thus a T-shape; it narrows below to an obtuse point, and, no doubt, supported a free diapophysis. The fragments of the pelvic and scapular arches indicate that they are capacious. The clavicle incloses a large foramen, and is thickened on the inner edge. The glenoid surface of the coracoid was wide and subrhombice. Some of the other bones are quite thin. The median suture of the ischium 12 ¢ 90 is relatively about as long as in the English Plestosauri, and the adjacent part of the bone has a similar form. Measurements. M. hen e throfethcantentoncenvica lee ayers esis tier tesa ete ee ere eter ee ee ee seem eee eee 0. 062 Depthiot theiarticularfaceof; thejanterion’cervicalle. - o2 ~ ac c= =e eles ee ete eel ee eeer 0. 050 Width of the articular face of the anterior cervical --.--.-.-- .-.- <2 -- - see cose s eee e es ene: 0. 050 Weng throfetheposterionicervicalesces. c=. 2s. sees sons en eae EpacoOGOQonD HAUsoo Sone So.odUSeU,SeK5 0. 070 Depthrof the articularjface! of, the) posterior cervical\s- 2-222. == eects eae eae eisinslexeie eee 0. 052 Width of the articular face of the posterior cervical... --- <2 -- 2s -6 seme meine = oe nee 0. 090 Mistanceybetweeniparapopliysialipitsy \se-e-soseae cee 1s ee eee eee eee e ee eee 0. 048 enethvorthejanterioridorsalliivertebray-.acisc soci c =e eee een eae eee eae eel eee eet 0. 059 Depthrofi thearticularifaceiof theianterior/dorsal!= 2-2. 2... see ee eee ee eae eee erect 0. 062 Widthtofathemiticularstaceof theranteriordorsals.--- ysis ee eee eee eee eee 0. 072 Widthyofathemenralicannlionithe centromices =e eae eee eee cena eee eee eee eee eee 0. 017 ongidianeteonthesproximalvendiot therclanicle seescsss ase aeeee ees) cere eee eee seer 0,114 This saurian is readily distinguished from the E/asmosaurus platyurus, Cope, by the relatively shorter cervical vertebree and.the regular acute ridges on the exterior surfaces near the margin of the articular faces, as well as the less contracted form of all the vertebral centra. As the neural arches and _ the cervical parapophyses are not codssified with the centra, the species is referred to the genus Plesiosaurus. ; The bones of this reptile and those of a smaller species, probably a Clidastes, were found in close proximity, near Sheridan, Kansas, by Joseph Savage, of Leavenworth. According to this gentleman, the vertebral column of the Clidastes was found immediately below that of the plesiosauroid, and in a reversed position, as though it had been swallowed by the latter, and larger reptile. The largest vertebrae of the C/idastes were about three-quarters the length and one-fourth the diameter of those of the plesiosauroid, and the animal must have furnished a large, or at least a long, mouthful for its captor. The bones of the Clidastes were not in good condition, and resembled those of C. cineriarum, Cope, though smaller. TESTU DINATA. This order is but sparingly represented in the marine formation of No. 3, and more abundantly in the fresh-water beds of No. 6. Of the former, there are three species, two of them with natatory limbs of the character now known among sea-turtles. Of the latter, all are Trionychide and Emydide; the land-tortoises not appearing among them, according to present information. Oil COMPSEMYS, Leidy. This genus presents the characters of Hmys in ‘its well-developed marginal bones, united to the costals by suture. The surfaces of the carapace possess a dense layer, which is sculptured in two of the known species. One of these, the C. victus, Leidy, has been found to have had a wide range in the West during the Fort Union epoch; while a second has been found in corresponding strata near the northern boundary of Dakota. CoMPSEMYS OGMIUS, Cope. Represented in the collections of the British American Boundary Com- inission by portions of the carapace and plastron. These are massive, and indi- cate a species of large size. As in other species of the genus, the external surface is a dense layer of cement or allied substance, which is sculptured with shallow pits. A portion of the costal bone is concave, and increases rapidly in thickness in one direction. The suture is coarse, but neither gomphosial nor squamosal. A portion of the plastron is thinner, not curved, and displays a very coarse median suture, in part squamosal in character. The sculpture consists of shallow pits, not wider than the low, smooth ridges which separate them. There are deep superficial grooves, marking the boundaries of dermal areas; a feature in which this tortoise differs much from the P. coalescens, and resembles the species of Compsemys. Should marginal bones be found to exist in the P. ogmius, its reference to that genus will be further established. From six miles west of first branch of Milk River, near latitude 49°. ADOCUS, Cope. Proceedings of the Academy of Natural Sciences, Philadelphia, 1868, p. 235; Proceedings of the American Philosophical Society, 1870, November. This genus possesses a large intergular plate. This I have verified on A. beatus and A. syntheticus. Having also perfect xiphisternal bones of these two species, | can show that there is no sutural attachment for the pelvic bones. The co-existence of these two characters has been hitherto found to be uni- versal, and the present deviation from it is a point of much interest. Instead of sutural surfaces, there is an obtuse ridge corresponding to the pubis, and a knob answering to the extremity of the ischium, both more prominent than is usual in genera of Hmydide. 92 This exceptional combination of characters points to the propriety of sep- arating Adocus as the type of a family equally distinct from the Lmydide and the Hydraspidide, to be called the Adocide. Further characters of the genus have been already pointed out in the later essays above quoted. They are: the free lobes of the plastron narrowed and shortened, furnishing extensive posterior and anterior entrances to the carapace; a series of intermarginal scuta on the bridge; costal capitula reduced or wanting. No recent or even Tertiary form of the Testudinata has yet been discovered which possesses the remarkable combination found in this genus; and I think it must be regarded as a generalized group, and as such of much interest to the student of paleontology. Apocus(?) LINEOLATUS, sp. nov. Established on a number of fragments from different exposures of the Lig- nite beds, primarily on a vertebral and sternal bone, from the Dinosaurian locality in Colorado. As the diagnostic portions of this specimen are wanting, it is referred to this genus provisionally, and because the structure and sculpture of the parts resemble most nearly known species of it from the Cretaceous greensand of New Jersey. The sternal bone is flat, and presents the median and transverse sutures forming the usual right angle, and of a rather coarse character of a median serrate keel, with pits on each side, for the reception of corresponding pits. The vertebral bone is rather thick, and is shallowly emarginate in front. The sculpture consists of delicate, obscure, parallel lines, which are more or less interrupted, and occasionally joined, so as to inclose, faintly marked areole. Measurements. MM. Widthyofitheivertebralbone;in Hfronte..cis-.s)en-. soaces o> eee eee en eee eee eee 0, 0135 Widthiorthe;vertebral) bone \(ereatest)..---<4-- 2 2=s-0-- sees snes ee ees aoe eee 0. 0280 Thickness! of the'vyertebral bone .si. 2 fc. se25 cbs 2 22 oc occ. Sere nse eee ee eee 0, 0070 Thickness7ofithesternal bones.-5- -<5-<~staae s2-5c-eces sos siess PE es EEO SOLSD From Lignite of Colorado, and mouth of Big Horn River, Montana. PLASTOMENUS, Cope. This genus has been discovered to embrace tortoises having characters of both Trionyx and Emys. The carapace is like that of the former, in the absence of articulated marginal bones, and the presence of a superficial cement layer, which is sculptured in various patterns. The plastron resembles that of some emydoid genera, but presents certain fontanelies indicating an incomplete grade of ossification. ‘The species known to possess the typical structure are found in the.Kocenes of Wyoming and New Mexico; and those here referred to it are all from the Fort Union or Transition beds of the Cre- taceous. In none of them is the sternum so well-preserved as to exhibit the characters which should finally refer them to the genus Plastomenus. This is due to the fact that they, as well as other vertebrate remains from this horizon, are always much broken or dislocated. PLASTOMENUS COALESCENS, Cope. This species is represented by large fragments of carapace and plastron of a single individual. These indicate a large animal of adult age. The fragments are thick, and the sutures separating the component elements have disappeared. Dermal sutural grooves are also wanting. The portions of the plastron preserved are emydoid in character, being most thickened in the lateral portions, especially in the inguinal region. The borders of the carapace are free and obtuse; at some points, somewhat thinned out. The ribs proper, in the portions preserved, terminate in a short, tree extremity, shorter than in most species of Treonyx. There is no indication of the existence of marginal bones. The surface of plastron and carapace is covered with a dense layer, which is thrown into rather coarse, inosculating folds These form an open, reticulate pattern towards the middle portion of the carapace, and become obscure near the borders) They are well-marked on the plastron, and are more or less longitudinal. ‘The appearance is that of a Trionyz. 8 Pl y The costal axis scarcely projects on the inner face of the carapace. The anterior border of the carapace is a free, thickened margin, divided by a hor- izontal groove. The presence of nuchal bone cannot be ascertained. Measurements. M. Thickness of the carapace at the middle of the length of a costal bone...-..-----..--.-----.---- 0.014 Thickness of the carapace at the anterior margin -.....-...-2-....-.-2--- 222-22. --+2 ---- ee = 0. 008 Thickness of the carapace at the lateral margin... ...2.. 2.5.2... 22-. 2-22-2252 eo eos Sees eee 0.008 Rhicknessjofmbolresplastronmmearth eno rid yelper ne eee sees eee ete eee areata eee eelaciasteee 0. 015 hickness'ofetherplastronpmorercentLallyeee eens ate ene eee see keener nen ceeeec ceca 009) Four areol in 0™,10. 94 This species is found in a greensh-brown arenaceous clay deposit near the Milk River in British America, belonging to the Transition series, probably the Fort Union or Lignite epoch. Collected by George M. Dawson, of Montreal, geologist of the British North American Boundary Commission, near Woody Mount. PLASYOMENUS COSTATUS, Cope. Represented, in the collections made by Mr. Dawson, by small portions of plastron and carapace, which display distinct osseous, but no dermal scutal sutures. These specimens were discovered together, and are believed to belong to the same individual. The bones are thinner than corresponding ones of the two other species of tortoises described, from the same locality, excepting at the costal enlargement, which is remarkably prominent and well- defined on the under side of the carapace. The dense or cement layer of the carapace is thrown into very delicate, but prominent ridges, which run parallel to the axis of the carapace, and occasionally mosculate, or are crossed by a similar ridge running at right angles to them. The sculpture of the plas- tron is similar, bat more obtuse and obscure. The superior edge of the free border of one of the lobes of the plastron projects beyond the inferior, and is not, as is usual, less prominent than the inferior. Measurements. M. Mhioknesstofalcostaliat the marge imeec cme asc ates <= oes sean miceiciat os leis etetee ciniae ie see ere 0, 005 Rhicknessiofacostaliatitheitbac- ere see ate sae na eee eee ee reese eee eee ee ee 0, 009 Mhicknessof the'freeiedreiof the plastron) --= 5 ae. aero oe ieee tee leet eee alee ete ei ee 0. 009 The costal bone of this species is much like that of a Trionyz, but the character of the plastron refers it to Plastomenus. Collected in the bad lands of the Fort Union Cretaceous, south of Woody Mount, near latitude 49°, British America. Associated with this species were the P. coalescens, Compsemys ogmius, fragments of perhaps Compsemys victus and Trionyx vagans, with Dinosauria, Cionodon stenopsis, etc. (See chapter L) ! PLASTOMENUS PUNCTULATUS, Cope. Established on a costal bone found in association with the preceding species, and referred to the genus Plastomenus provisionally, and with a possibility that it will be found not to pertain to it when fully known. 95 That genus has so far only been found in the Kocene formation. The bone is rather thin, and sufficiently curved to indicate a convex carapace of moder- ate thickness. The surface is marked with closely-packed shallow pits with- out material variation of form on the proximal half of the bone. The result is an obsolete sculpture quite similar to that seen in some species of the genus to which it is at present referred. Measurements. M. Wridthrotithercostalk bone secre eer ee erro ee ct oercity acinar ERE ernie oe See eee 0. 0230 Whickness:of the icostale ponerse execyee ere eee eas eae ere ees EP ee ees a eteseeye ies 0, 6033 Number of pits in 0™.010, 6. Lignite Cretaceous of Colorado; also, several fragments from Long Lake, ‘‘ Nebraska,’ from Dr. Hayden. 1 PLASTOMENUS INSIGNIS, sp. nov. Represented by a portion of the right hyposternal bone of a tortoise about the size of the last species, and from the same locality. The specimen resembles, in its sculpture, such species as the Plastomenus trionychoides, and, in structural character, the species of Anostira, but it is scarcely probable that it belongs to either genus. It is flat. and has a narrowed, straight, inguinal margin, at right angles to the fine suture with the hyosternal. The suture with the postabdominal is partially gomphosial. Surface dense, polished, marked externally with a reticulate sculpture of narrow ridges separating larger and smaller areas wider than themselves. Inguinal edge thinner. Measurements. M. eng thiofthe hyposternaltforerandsattienee see eaeee eee eee eae aera eee e eee aia 0. 025 (Rhicknessioficheyhyposternalkateronteees ace e eee re eee cere ees ee eee tener een 0. 004 Pits in 0™,010, six. Lignite Cretaceous of Colorado. Revie TRIONYX, Geoffr Although species of this genus occur in the greensand of Cretaceous No. 4,in New Jersey, none have been discovered in the West below the horizon of No. 6, or the Fort Union fresh-water beds. Dr. Leidy has described a 7. foveatus from the bad lands of the Judith River, Montana: and I have added the following: 96 'TRIONYX VAGANS Cope. Bulletin of the United States Geological Survey of the Territories, No. 2, 1874.—Triony« ? foveatus, Leidy, Proceedings of the Academy of Natural Sciences, Philadelphia, 1856, p. 312. Represented by a number of fragments of costal bones, and, perhaps, of sternals, also. The former are rather light or thin for their width, and are marked with a honeycomb-pattern of sculpture, in which the ridges are thin and much narrower than the intervening pits. They incline to longitudinal confluence at and near the lateral sutures. Several areze are not unfrequently confluent in a transverse direction near the middle of the bone. Measurements. M. Width.of the costal: bonescis sss.- no06 nadoed Good coeds Sea dsocuD HENS CoSoSa DOU SoU ecEb nDSo So ocasEcHnEeaEse 0. 250 Widthrotathercoracoidadistallysessseseseretitasaieseatseeaiseae eens eetesieeedneiecias een ncaa eee ae 0. 080 Bensth ofthe ramus) of theymandibl eet sem == = sein celeron em eizloiesin oacis cee sno-\ese=sele= == = o> 0. 157 Length of the symphysis of the mandible. ---.---..-.----------- 02. -- +--+ --0- 0 eee eee eee eens 0. 03 ~Hlevationofthercoronoidtofsthermandiblesaemercetasaetsanieece eeciee eine eeceiescieceien eee iee sees en ONU4S Widthrorthesansleofsthelcoronol dearer -cemcisionsenenisalstosiesmerienciiecnsfeisiaiseest==-e nace =s ee UN02d The axes of the mandibular rami produced unite at an angle of 65°, indicating a muzzle of intermediate length. The size is about that of the existing loggerhead (Caretia caouana). Found by Professor Mudge near the forks of the Smoky Hill River. NN f Fig 2 3 | 2 I 6 ; =a \\ x i EN ig i Fic. 2.—Sketch of the large radiated bone of Protostega gigas, with other elements, as they were uncovered by excavation; size much reduced, drawn on the spot. Nos. I, VII, VIII, and IX, costal bones, with the rib-heads looking upward; X, the coracoid bone; 5, a marginal bone; 9 and 10, the lateral a radiate bones; 16, vertebra, with other bone adherent. PROTOSTEGA, Cope. This genus is the type of a new family of tortoises of the suborder Athece, characterized by the lack of expansion of the ribs into a bony roof, 100 or carapace, and the development of independent superficial dermal hones. The dermal bones consist of large plates lying above the ribs, which have no sutural union with each other; of some small vertebral shields on the dorsal line; and of thin, marginal bones, which have no sutural union with each other or with the other bones. The vertebrae preserved possess ball-and-socket joints, and have flat neural arches, with widely-spreading articular processes. The humeri are flat, and furnished with an enormous deltoid crest. The fore limbs were very long, and formed flippers like those of the marine turtles of the present seas. The bones of the head are very light and thin, and mostly united by squamosal or overlapping sutures. The mandible presents the elements usual in the marine turtles, and has no angle. It exhibits a deep pterygoid fossa, and is very light. The constitution of the bones is rather dense, and there are no medullary cavities whatever. The superficial layer is very thin and striate. The bones are all very fragile. The atlinities of this genus appear to be largely to the Sphargidide. This family is represented, in our present knowledge, by but one genus and one species of the recent seas. It is one of the most generalized, or, in special characters, the most aberrant, of the order of tortoises, and the dis- covery of an extinct ally, even as far down in the series as the Cretaceous period, is not surprising. The remains preserved belong to a single individual, and include many portions of the cranium, five vertebrae more or less incomplete, the scapular arches of both sides, with the coracoid bones; both humeri perfect, with nine phalanges, ten ribs, one vertebral(?), and ten marginal bones; parts or wholes of four large lateral (?) dermal bones, with five distinct bones of unknown reference. There are also some slender curved bones, which probably pertain to the plastron. As the bones were exposed by excavations in the yellow Cretaceous chalk, sketches of their positions and relations were made, which aid mate- rially in the restoration of the animal. The upper layer of bones were those of most irregular form, as cranial and limb bones. Mingled with these, but often beneath them, were the ribs; while underlying all were the large flat pieces here described as dermal. Adhering to the inferior surface of these was a layer of thin oyster-shells, with parallel striate surface, perhaps Inocerami. The ribs presented their heads upward, so that, taking all points into con- 101 sideration, there is little doubt that the reptile was entombed lying on its back. The texture of the bones is peculiar. There are nowhere to be seen medullary cavities, and the bone is spongy, but very finely so; the tubules at the largest being equal in diameter to an ordinary pin, and generally consid- erably smaller. ‘They are arranged in concentric series. ‘There is no thick dense layer of the bone as in other tortoises, but an extremely thin one, which is hard, and sculptured on the surface with minute grooves or pits. The tissue of the bone is very fragile, and has a fracture like the mineral inclosing it. Many of the bones, especially those of the dermal skeleton, are extremely attenuated on the margins, being no thicker than writing-paper. In discussing the affinities of this genus, one doubtful point must be considered. The large flat elements described as lateral dermal bones, are they ossifications of the dorsal or ventral integument? They were found below all the other bones, and nearly all the ribs laid on them with their heads turned upward. This rendered it probable that the shields were dorsal, and that the animal was entombed on its back; and a coracoid, which was afterward found lying immediately on the largest bone (No. 10), crossed in its course parts of two ribs. This could not have been the case had the shields been ventral. An examination of the shields does not reveal any conformity to any known type of Testudinate plastron. The bones radiate in all directions, leaving no margins for fore and. hind limbs, or for a median fontanelle, still less for suture with each other. ; Should these bones then be regarded as dorsal, they constitute a charac- ter not previously noticed in the order, but one whose homologue is seen probably in the dermal shield of bony tesselated plates seen in Sphargis. The other points of affinity to Sphargis are the distinct ribs; the thin lamin- iform jaws with cutting-edges; the quadrate bone with such a strong anterior concavity ; the elevated position of the zygomatic bone; the form of the humerus. Points of special resemblance to Chelone are: the short posterior superior portion of the quadrate; the entire edge of the maxillary bone; the deep dentary. © The points in which it differs from both are numerous. They are: the dorsal shields; the marginals; the notched symphysis, etc.; the shortened articular end of scapula; the elongate form of the carapace, ete. The constant separation of the ribs and the short vertebrae are charac- ters which are more like those possessed by other reptiles than those charac- 102 teristic of Testudinata. The preseuce of dermal dorsal bones is of the same kind. The genus Protostega then belongs near the Sphargidide in the sub- order Athece, and is in some points to be approximated to the Cheloniide. PROTOSTEGA GIGAS, Cope. There are twelve marginal bones. They are all characterized by their laminar form. The thinnest are those farthest removed from the middle of the sides. They consist of a single lamina, slightly thickened within the margin, producing a slight convexity of the lower side. The proximal part of the bone is an extremely thin plate, with radiating ossification, and conse- quently more or less serrate margin. It extends some distance over the extremity of the rib, whose apex is received into a half-pit or acuminate groove with abrupt termination, about one-sixth the width of the bone from the margin. In following the marginals to the middle of the side, the edge, as usual, increases in thickness. The lower side becomes more convex, and the upper slightly concave. The edge is acute, with a very open interior entering angle at the middle. The lateral extremities of the marginals are irregular, termi- nating in a double series of closely-packed digitations, which terminate freely, and enter into no suture. The pit receiving the extremity of the rib ap- proaches the margin, which now develops an inferior lamina of bone. This incloses the end of the rib, and thins out laterally in contact with the superior plate. In some, the inner lamina is short; in others, it is almost as extensive as the outer part of the marginal plate, causing the double appearance when frac- tured. As the marginals thicken, a distinct inferior plane becomes distin- guished, separated from the interior face by an obtuse angle. The upper face near the margin is more concave. In the thickest, the inferior face is also somewhat concave, and the edge quite acute. The lateral extremities consist, as before, of packages of digitations, which easily break out. A single nearly bilateral bone of this series appears to be either nuchal or caudal; but, as it has no sutural connection with any other, it is not easy to determine which it is. Its marginal length is much less than its transverse extent, which consists chiefly of a flat lamina. The marginal part is a little thickened, and bilaterally concave below, and correspondingly convex above. The margin is thin and acute. A few grooves radiate at a distance from the middle toward the margin. The lack of concave excavation of the margin would incline the balance in favor of the view that this bone is the caudal. 105 A very long, gently-curved bone is probably the marginal extending on one side of the nuchal. It is nearly twice as long as the others, and has an extensive and thin superior lamina. Its ? anterior part is in one plane; but the margin soon thickens, and displays a rather wide infero-external face. It appears to have had an inferior lamina on its posterior half, which made an angle with the face just described. An oval cavity included looks as though designed for the apex of a rib. The variation in the lengths of these marginal bones is noteworthy. I give measurements, premising that a few lines may be added to the extremi- ties of some for lost digitations. Measurements. M. ihenothvofetheslongranterion @upin ches) ej eay eer eels emiceeer lacie chem eter ies eriacl ere 0. 28 Widthofthemoneianterior (SomeylOsh)m merietas see erate cis aasele selec eines cee eee eee een ONL oO hencthvor pheylateralgwithytheyn terion tice seneese\=si cielo eeieeac-eecioceisiee eee ceieseeeacite se ee oD Wiadthvotthe lateral @muchtlost)Passsesieeeceseciee ce sci esis sce eicance eater eee rice asec eeeee AO sLlO Heng thiofthe lateral with narrower inferior face) —- 2.0. 2-22 -222- .nc6 ---)- ae) ee aee sea eee 0. 206 Widthof the lateral (muchylost)fsescesis= else acm cerane eee eieteeeee ease BS aaa nite aise 0.115 men othroroneswathithesinberionrslaminiapeceecmesectessee cies enscececeiseccccer eee cm aeecrate see 0.14 Widthrofonel(sometlosh) passerines ed eects ei eee ene ee ere eee le en een aera 0. 086 ene throMathinnersnomn tenor) wereeeestcne tear aesieeeeeiacee seecee acct ae cee eee eae 0.193 meno throtaysilkchinnermonnterior plateyceeete ss sears asec eee eens teeeeree seer eee 0. 182 Wiadthvotrarstillathinn ers (broken) meeemstaceeeinace cee cence canes ccieee eee see ee eee 0. 137 hero thao fathexulinnestesseereree sees eee elec area eee eee cers ae ere ee aie eae eee 0. 162 Wadthtottheythinnwesti(mearlyicomplete)issessasce eee ien eee te ceeice aicia emia ee eeitee eee eee 0. 160 H CAI INGMGINS 6845 sqaqodacsas seco donebn coded Dobbes Baca Boose eases mae oeoesneceHo cose saad daas 0.117 CECH \iGliiNeton. sob eh 65H aauo oodoas ae cea U be oeOuoBEa shad. daseeabone paaemenelseda cance otbode 0. 150 The shortness of the marginal with large interior lamina is noticeable, as also the same peculiarity in the caudal. As compared with marine turtles, difference is to be observed in every particular. Such are the lack of. sutural union; the laminar character; the great extent of the superior and distinctness of lower laminze. There is no trace of epidermal sutures visible anywhere. A single symmetrical plate appears to have belonged to the middle line of the back or nape. It was subtriangular in outline, all the margins very thin, and with an obtuse keel extending on the middle line, on the posterior (or anterior) two-thirds to the apex. This ridge disappears in ?front by a gradual expansion The surface is marked by lines of minute pits and grooves, which radiate from the base at the (@) front of the ridge. Length, Ores a awd then Oneoile The /ateral dermal bones preserved, are two entire, and large parts of one or two others. They have an irregular oval outline, and are slightly dished on the inferior surface or that next the ribs. The upper surface is 104 more convex longitudinally, from the thickening of the bone. The margins are irregular, from the projection of many digitations. Some of these are broad and flat; others are narrow. They are frequently two deep, and the fissures separating them occasionally extend far toward the middle of the bone. The convexity assumes the form of a low ridge toward one end of the bone. At the point where this reaches the margin, the latter is in all the four plates, thickened, and composed of several layers of packed osseous radii. When found, the ribs laid across these shields, one of them occupying the position of a radius to one of them. These shields are much larger than the marginal bones. Measurements. M. Ibe yA Oye aN fay, OY (ALIBI) Soo 55. coaojoosoos hoSoeosaeas6 cobEss 5 Boone OnciadeSebeas banseo ass 0.535 Wid thvoftSN os O24 Gb ro Ken) eee eters mate tate e a e im oareee ae er oer elle eee 0. 400 hickness;atitheimiddle.secsasscs-- ces emcee ceceee teee = eee one aa sale e cece eee eee 0.014 henethiof N019 72 cen ccs ema ecsmee eee meee seca settee ne ceien = soles ete sa ae eeen ee eee 0.530 Width) of<°No-97 (muchsbroken)) <25-2---e=-2-ss= =~ = === =1— BAD Batson SEO bee Gees casa caee node 0.350 Mhicknessiatithemmiddle seeas-s- seer eees eee ete == BSC OE TOE Bae RSS Cee CORSE OOS BamO oS 0.013 The lengths and breadths given are a little below the truth, owing to the loss of the exceedingly thin margins. Turning to the endo-skeleton, the vertebre deserve mention. There are more or less complete examples of five of these; in two, both centrum and neural arch, in two neural arch, and in one centrum, are preserved. These have been recognized chiefly by their neural arches, which are separate. They are in form something like an X, the extremities of the limbs carrying the zygapophysial surfaces. The only point of contact with the centrum is a wide process, which stands beneath the anterior zygapophysis, and spreads out footlike obliquely forward and outward, to beyond the line of its anterior margin. Its surface extends nowhere posterior to the surface of the zygapo- physis above it, but a little farther inward. Its outer margin rises ridgelike to the under side of the neural arch, and each one, forming a semicircle, forms the boundary of the neural canal, and, turning outward, forms the inner boundary of the posterior or down-looking zygapophyses. The space between these apophyses is roofed over, so as to produce a shallow zygantrum, which, however, only seems to roof over the deep emargination of the neural arch of the vertebra immediately following. The anterior zygapophyses are often broken away, so that the neurapophysial supports look like the missing pair, when the difhculty ensues that both pairs look downward. The top of the 105 neural arch is, in two cases, broad and flat; in two others, there is an obtuse keel. The centra, apart from their arches, are puzzling bodies, especially since in the present case, they are somewhat flattened by pressure. They differ materially in size; one of them being twice the size of the others. The smaller ones are of the ball-and-socket type, and have a deep longitudinal groove on-each side. The thicker portion of the centrum forms the inferior boundary of this pit-groove, while a thinner portion, possibly a diapophysis, limits it above. It is, however, thin, and had no great length. There is no sign of chevron bones and articulations, so that these vertebrae may have been cervical. Their bodies are, however, shorter and wider than in those vertebree of any known tortoise. A groove on the upper surface represents the neural canal; while a flat area on each side, in front, supports the neurapophyses. The large centrum exhibits the superior groove and antero-lateral platform for support of the neural arch. One end is cupped obliquely, while the other is nearly plane, with the same obliquity and a slightly-raised margin. Its outline is subtriangular. The lower side of this centrum possesses a short keel posteriorly. The sides exhibit no pit, but have a thin edge, which is concave behind the middle, and then turned outward. I can see no articu- lation for a rib. The forms and characters of these vertebrae resemble Sphargis more than anything yet described.’ Hither the large or the small, or both, must be referred to the dorsal region; in this case, the concavity of one extremity is a new feature among tortoises, so far as known. The great freedom of the arch from the centrum is very peculiar; while it is probable that the articula- tions of the ribs were to the middle of the side of the body, and not to the adjacent parts of two bodies, and may have been (see below) to processes or diapophyses. Measurements. wo ihenpthyofthepmedinmi centromeres cecece secs ae eee ace eee clec en oie ee eee ee ie saeeecieiee at On 0ad Width of theimedinmicen trumps seco neen enact eee ciee eo eieeietieenieeneicineeices cee o sees nceaaee 0. 060 Length between the margins of the zygapophyses of the medium centrum..-..----------------- 0. 060 Width between the anterior margins of the zygapophyses of the medium centrum...-.--------- 0.070 Width between the posterior margins of the zygapophyses of the medium centrum - ------------ 0, 047 Width betweenitheanterionibasesjottheiarchys-e 5 ssecee teseeas 2 sae eeeoene Inca esos ne== 0. 070 WAKA. AHO En NS TGONG wcecessaueooocesesbotae 5 Hebets sooccuadebcoseaseecca ssaneesue 0. 028 Renothiottherarchiatachepmid dleneessmmr ae nel aaeci yarn yeti sens eee ieee eens eeeeelee m= 0. 040 Width of the posterior etapa aa Oh IN), BSSe pebieesodenooe ne Ser Ron eaateeeceesoreEsoecuesese™ 0. 048 Widthvotstbhetarc htc re tre sevens rae eres sete le em ee aes acts or si Bae Sie carte Gers apseine teeta teein eciceies lee 0, 025 1See Temminck and Schlegel Fauna Japonica, Reptiles, Tab. 1-4. 14¢ M. Leng thyof-the jarchynpaen cose jaeiesc asia setae cee aa oseeseele ss ceisei tins cain eee eee ee ae eee eee 0. 025 eng thyorgtheyanteriortooLy(Oblique) pases weecer eee sereesesciasieeeeemerice sac ee eeer eeeeeenee 0. 020 Hengthforthexcentrumkofathelargelonesssecs sac ee sees aeene ss asso eines nne eee seen eters 0. 060 Wadthyotsthercentramvyotsthellarceioneea serie liseiseslsl= a ei-an isieetieeieee tse e eeeee eee 0. 094 Waidthvofthemenraltcanalkor the llargeonosssasse steerer sees shee einen ieee ae alee eee e eee 6. 017 Ten 7ibs were recovered. These are slender and rather flatter than in most reptiles, but without the peculiar form characteristic of tortoises and turtles. They are most expanded proximally; the bone spreading into a lam- ina from the tubercular region, extending laterally and proximally some dis- tance beyond the head. The superior plane of this expansion is continuous with that of the rib, and is flat; the head ef the rib therefore turns down- ward and inward from it, to join the vertebra. Now, the extent of the inner part of the lamina is such that, were the head articulated to any of the cen- tra discovered, the laminze would interfere or overlap. They may, therefore, have been articulated to diapophyses. The expansions are serrato-digitate on the margins, and exhibit radiating grooves and ridges in some places on the superior aspect. The lengths of these ribs are not so great as the pro- portions of some of the other bones would indicate. Measurements. M. Teens thiorONos Vile C16 inches) ss .2sc=- se sas a esiswes occ toc c ee See cere eee ene eee 0.510 Widthtatithevheadss29.2 5.8 oss ee cere nce Ne eee Seine Se ae Ps ee ae ne ee 0. 140 Wiidthiofithethead:, oss. .- 5 esses coat vec Ow oe soe encloses eee nee cee EEE eee eee 0. 040 Widthvatithemmiddlerssscsssct s- ce close nacareseseereen cose scene bese Gees se eeise etre ns See eee 0. 055 Waidthyatithe extrem bye ee nacro = meee tees hee ata etal ete eae ae eran ee ee ONO) enoth of SNow llc sisslesioaee oe oa cre ce Sete ee Se he Se ae a oe 0. 390 Wid thyof So No.2 juspibelowsthoheads-s--sscesseecee se eaeee ees se eees eeee ease eee eee 0.100 Width atithe:middle::. 22 sso.-..scees seco se kt oe ste ane ae ee we ee 0. 037 en gthiobSNoGix ices es oe ee OE eS RE ee eee eee Sou toeeeaeee 0. 380 Length proximal tosthevhead <.5-22..202-.i 2 cccecen oot loca esnicecs Dee eS eee 0. 060 Widthiatithesmiddle scans. 5 a2 se ecn wee ose ences nos oes ee ee ee ee Sefsa eee aaates eae 0. 080 In the rib ‘‘No. II,” the head is turned obliquely to one side, indicating that the rib diverged at a strong angle from the vertebral column; in fact, not more than one of 45°, ‘This is, then, an anterior or posterior rib; probably the latter, since the shell is usually expanded chiefly in that direction. All the ribs are flat above, and convex inferiorly. Both sides of the scapular arch are complete, except the sutural portions of the coracoid and scapula of one side. The scapula and procoracoid make a very open angle with each other, both being stout; the scapula the longer, with grooved sculpture at its proximal end. The procoracoid is a little the shorter. The glenoid cavity and coracoid suture are almost sessile at the 107 union of the scapula and procoracoid. The coracoids are very elongate, almost equal to the ribs, and not stouter except at the extremity. It is expanded into an oblique head proximally. The shaft is flat; one edge thick- ened or truncated; the other thin. The distal portion is scarcely expanded ; being more slender than in any recent Testudinate known to me. Measurements. NM. Length of the scapulaito the clenoid/cavity ---- 2. -- .2- 322 = ceceee oo ese e ore e cee eec ener ease seeee- 02213 Widthtonathescapulasproximalllyeeeeeeee essences eee eee eee eee eis eases ot ONOAD, Length of the procoracoid to the articular surface... -... .----- ----56 -2 25-2 ooo nee ere wo eee one 0. 106 Widthtofitheyprocoracoididistallyeeeeeese serene eee ee eee eee eee ease ee eee eecieeecieses 0. 060 Beng thiotthercoracoidiemeestascecer cae se eee cee ee eee cen et ee eo eciece in eeac ea anienas 0. 400 WAG NOH pmb re ca Soa6 cpmcos booees.auoccasdaede Goannd GesRHe Hdobod cos Ecapodoro bosaes bacood 0. 086 Wid thyvotime dialliy seers = crs stamens ratee See ie ee aloe roreie cS ae toe ale net aasiceene siete oh saiosalal= aie 0. 047 Widthiotedistally2c2 sce nsee sence see ssierose cite nei snajee ene selec cs lesecersscsioneisecisieaaete seins 0. 080 The elongate coracoid resembles most, among recent Chelonians, the marine genus Chelone; while the sessile glenoid cavity and short procoracoid with open angle are entirely different. In these points, this genus is more like terrestrial forms, as Testudo, or less like Emys. Both humeri are entirely preserved. 'They appear to have been some- what flattened by pressure; but, when unaltered; they were, no doubt, flat, with stout proportions. They have a globular head, with an immense trochanter, which projects much beyond it proximally. The shaft is then much con- tracted, and expands again distally to the broad and very convex articular extremity. Opposite the narrow part of the shaft, the small trochanter appears on the inner side, forming an elongate ala. The long axis of the humerus is*not straight; the proximal and distal portions making an angle of 110° with each other. Measurements. M. Dotalilengthyoftheshumerus) (foot) istrarohteseeemree eae) este eisieet eee iesieiioe iste ioe eee 0.300 eno throftheshumerusHrombtheyheadweas-s eee eee ee ae ee ete ee eeene ee eee eee oe eeee eee 0. 296 Wiidthyat Ghesbeads 23 so5 se tamer ee pee Seale ee eee cee Oo SOL Se SORES Sones aimee s 0. 156 Wridthrof; thevhead ss separa cro crete ta ee ese sake ete a aon aiSTaS Seo ISTO eee elocinclomeemeisaed 0. 073 Beastiwidthiof.the shatteaecestacc mice sate ese ne otto re nice ha ss wee coe cee erosion eee etoeusce 0. 076 Greatest distalawidtheaces--os-seeeee sere eee ee eeae Sates SSE ae CHS EOE Sebo S aoe EEE Re nce 0.132 hen thyofstheybasisiotatheslittlejtrochanteres-ssen-eaee eee ae eae noes oeeen eeneee cece see 0. 080 phickness:ablibheysh ad tese see eee State recreate tate eae see oeiecls one celine ceil earreraneteos 0. 031 The flatness of this element, and situation of the large trochanter in the general plane, are characters of the Sphargidide. The great constriction medially and expansion of both extremities remind one of the mosasauroid humerus. 108 Of bones of the fore-arm, there may be one; but the bones next in size to the humerus look more like metacarpals or metatarsals. Two of them were found together in position; and their relations were not like those seen in the fore-arm of sea-turtles. They measure over seven inches in length, and are strongly concave on their adjacent sides. One of them is slightly concave on the outer side; the other convex, the convexity being at two-fifths the length from one end. The ends of both are a little expanded ; and one end of one displays a double or trochlear extremity. The same end of the other is injured by pressure. A still larger metacarpallike bone is relatively more expanded at the ends. The articular surface of one of these is wide at one end, and much narrowed at the other. ‘The smaller bones, undoubtedly phalanges, are six in number. They are quite slender, a little expanded at the ends, and flat. Measurements. M. IUGR Oe HAG EMP) G5o056 SSCaCd GOUODI DOGO faanesg Sen0 case sSibesoCDUROSOS chad ecoSte cossou eau6 0. 165 Widthiof theilargest/atitheiextremitye-- =e. nce ence = cieeasloae mee eninwae dane acess neat eae a 0. 065 Widthiotithe largest abithe middle: seaneasa-ea coe aan loan eames eee ene san an sae ieee 0. 032 eng thiofthelongestiombtheypaensesetease eases ecisesiecee eeaeee rece ae seen e eee eee 0. 180 Widthratithelextremity-en- oscme saat sais to selma anete see imelee saete ciate arse nine aie eee 0. 650 Width ofthe: shatt x oe oo). oop on connie Sh ocaere scien soe cce cee se eeaie= jeaetosieisisnis tine cee ecemee oe ObOR Weng thiofatheiphalan gence. sets a/enciows sae se sce cscs ean aynn cease ee ieeieein cia ine ae sateen ee 0. 132 Wiadthiatithetextremibyjosstececice cence se eose = Seni setae tae eee ee eee eae eee eee eee ee 0, 032 Wadthvoritheishaftireesmctsccrisa= set leneene seca seat eet eae ate aa aa ee eta eet eee 0,018 Mhicknessiomtheshattecas ances cisco ceiee nee ee aera elotaeiea eae een eee nae eee en eee eee eee 0. 011 These measurements indicate, for the fore-limb, a total length of 4.52 feet (1".347) if proportioned as in Chelone; this would give an expanse of 11.3 feet. If, however, it was constructed on the plan of Sphargis, the expanse would be nearer seventeen feet. Several instructive cranial bones were preserved. These are the maxil- lary and distal part of the dentary of the left side; the posterior part of the left mandibular ramus; quadrate bones and adjacent pterygoids and squamo- sal, one side with the columellar plate; right postorbital bone and part of the left; also, some probably hyoid elements. The mazillary bone and the dentary present a considerable extent of the alveolar margin. This is remarkable in being thin, sharp, and elevated; without horizontal portion. The former bone is but little incurved to the premaxillary suture; its anterior outline is elevated and vertical, the nostrils entering opposite the probable middle of the orbit. The palatal plate of the maxillary has no great antero-posterior extent, so that the inner nares are 109 opposite the anterior part of the orbit. The latter presents only the anterior and inferior outlines in the specimen. The part of the maxillary below it is very narrow, and weaker than either Sphargis or Chelone. The cutting-edge has a very open sigmoid flexure, the suborbital part being turned inward, the anterior part a little outward. The osseous rim of the orbit projected out- wards considerably beyond the plane of the maxillary anteriorly. The dentary bone is very deep anteriorly, and, like the maxillary, is a thin, vertical lamina. The lower anterior angle is truncated by an acute, concave margin. This is the anterior extremity of the symphysis. This suture occupies the inner face of a triangular area, which extends but a short distance on the lower margin of the ramus, and then passes upward and backward for a short distance on the inner face of the ramus. That portion above the symphysis diverges outward; thus producing a deep notch at the symphysis, as though designed to receive a beaklike projection of the pre- maxillaries. The cutting-edge has a slight sigmoid flexure, corresponding with that of the maxillary; it rises into a projecting angle. The posterior part of the ramus displays the cotylus, and, in front of it, a deep, long fossa behind the articular bone. There is no angle nor coronoid bone, as in all marine turtles. The superior margin of the dentary is thicker posteriorly than in front; and its outer wall is produced backward as a thin lamina, covering the surangular almost to the posterior edge of the ramus. The angular is, as in recent forms, a narrow, wedge-shaped piece below the dentary and surangular. The posterior edge of the surangular projects behind the dentary, and exhibits an acute, convex edge rising forward. It supports a small part of the articular cotylus on its inner face. Most of this portion occupies the extremity of the articular. The latter sends a stout lamina obliquely upward and forward to the lower posterior part of the dentary. The quadrate bones are of peculiar form. They exhibit the usual poste- rior curvature above, with a shallow funnellike fossa for the tympanic cavity. It presents two strong ridges anteriorly, an inner and an outer, which inclose a deep, vertical concavity. The inner exhibits the suture with the pterygoid bone; the outer, with the zygomatic. The superior border of the quadrate within the squamosal is massive, and not inflated. Its surface is thickest where the usual articulation with the opisthotic exists. The posterior hori- zontal is short and deep. The transverse part of the bone which supports inferiorly the exterior part of the condyle is thin, and disappears above to the 110 antero-posterior portion. From its middle upward, it supports the zygomatic. The latter has no great extent anteriorly to its malar suture; and its inferior margin arches high above the line of the condyles of the quadrate. The pterygoid bones are subtriangular in outline, with concave sides, an emarginate base, and a very obliquely truncate apex, which articulates low down on the quadrate bone. Both margins are thickened and rounded; the superior as a boundary of the foramen ovale. The posterior margin of the platelike columella overlaps it on the inner side, deeply notching it; on the outer side, the suture is zigzag and transverse. ‘The superior part of the bone is produced like a flat rod, and, at its end, exhibits a squamosal suture for union with what is, in the snapper, a postero-inferior rod-like prolongation of the columella. No such process of the columella appears to exist in this species. The columellar plate is half as large as the pterygoid, and exhibits the oblique suture in front for the descending lamina of the parietal. The postfrontal bone of the left side is preserved entire, and the inferior portion of that of the right. The inferior margin for the malar is the longest, and is straight. The orbit is excavated in part from its anterior margin; while the supero-posterior is a continuous curve. The inferior suture is a groove, whose inner bounding wall is convex, but rises past the straight outer to an inner ridge, which probably approaches the ectopterygoid region. A large sutural face for the zygomatic exists at the lower posterior angle, and an elongate one above for the parietal. The inner face is concave, indicating a large temporal fossa, as in Sphargis and Chelone. Two bones, of opposite sides of the cranium, are either those portions of the pterygoids which bound the temporal fossa below in front, or those portions of the maxillary bounding the palatine foramen. As the free margin is much thickened, they are probably the former. Their inner, or thinner, Jamina is marked for squamosal suture with other bones, perhaps columella and palatine. Measurements of the cranium. M. Depthyoh thepremaxillany/sutnre ofthe maxillary 22-2. - ~~ ose ee es oe eee ee eee eee eee eee 0. 060 Length from the premaxillary suture to the inner nares..---. 222-2. 222. cece e ee nee wenn ones 0. 068 Depth of the maxillary below the orbit .-..-. ..---. .--------. SOR OSeo EDS NSa Doo Sse. seoccnes 0. 035 Depth of the dentary at the symphysis ---------.----- 2 oe eo ne woe ene ween nee 0. 07 Depth of the notch of the dentary at the symphysis ----------- <5 ooo. once conn cone ee eee nee 0. 044 Depthiof theidentary behind! theisymphysis----—- 2 — << <2. os en een ee eee eee ee eee EEE 0, 095 Depthiof the dentary ati the coronoid'retion- oe oe ee ee 0. 085 Depth iof theiramus)at the frontiof£ thelcotylus 2. < on a oo en oe CD henpthrof the;pteryeoid tossp of theicotylus 224s. s2----\--5 2-022. ooeaee eee eee ee eee EON ODO M. Length of the cotyloid fossa..---.-----. .----- ++ +--+ +++ 222 soe noe ne eee oe eee co eee oe eee eee 0. 070 Length of the postfrontal on the inferior suture.....-----..-----.--- +--+ 2-2-2 eee eee eee eee 0.195 Depth of the postfrontal at the boundary of the orbit.....-...--..--.-------------------------- 0:136 Thickness of the postfrontal of the lower suture. ......-.--..---.-------+---------------------- 0,019 Length of the postfrontal from the orbit ee pe Pewia tale toute ois esaes sereecs Seee ase nees ae 0.115 Length of the right quadrate-------- ~~ 2-2 -50 a n= oe on en ne ee nee eee ee ---2---- 0. 140 AWA (Grave RO WeUEIMOD))s 5555 caso con chos codaoced aa60 cocc cone nan0 o6gn pean decece seca pueceoueon Wb ilk) \WUEGLAN @P TNE COMI A@sso0 dade dooseo peop neo bade BHod dose onde tags d000 doEE poop cede sede capoesereS 0. 064 Length of the right pterygoid superiorly -.....-.-------2..---------5- ----- ee 2-2 eee ------ (0, 155 Depth of the right pterygoid at the inner columellar angle ......---......----.-----+---------- 0. 100 en=thi (oblique) of thexcolum clay eecrs\-talstelet stale =) ae ala amit lalallala =letala ala) =l=iasalale simi iai=)= are 0. 085 Restoration—Better materials exist for the restoration of this species than ig usual in the case of most extinct Testudinata. The cranium was 0™.50, or 243 inches, in length. Ifthe neck and carapace were related to it as in the genus Chelone, the total would be as follows: Inches (Ghepbah ooo godecobaosoo uSthond cbeSde HSceEs cand ndedeo asobd.coodbs cé6ng5 Gos noosdanobeSE GEboSS 248 INGO ke GING | GAMERIEKES) cc odudos oaks sds soSboo dusd code pase cas pods epen seg nUGd BHbSd cooooseSoN go50sa 138% Noma; TRUS) 2s) iooodosde soa cass Sodosd Hdos eo dé0o oguS Beeb odes Shes Sead cabo bod coda HboS 0560 162% an extent not far from the expanse of the flippers above given, viz, 11.30 feet. The shortness of the cervical vertebree indicates that the proportions of the neck were not dissimilar to those of the existing marine genera. The flippers were probably similar to the same; of the hind limbs, nothing can now be stated. The shortness of most of the ribs, considered in connection with the length of the marginals, is remarkable. Thus, the longest rib measures 0.51, or 16 inches; width of lateral marginal beyond. apex of rib, 2.25 inches; width of vertebra, 3 inches, which is, however, covered by the expansion of the rib, included in this case in the length, 16 inches; total width of cara- pace at middle, 863 inches; length of carapace, estimated from cranium, 118 inches; or, width, 3 feet $ inch; length, 9 feet 10 inches. An outline, twice as long as wide, is justified in measure by the size, especially the lengths, of the marginals, which, if placed end to end, would measure on one side of eleven pieces, if each were as long as the median, 8.5 inches X 11 = 7.8 feet. Some of the posterior marginals are shorter than 8.5 inches, while some of the anterior appear to be longer. The length, 8.5, may then be takea as an average. But they formed the circumference of an open arc, so the axial length of the carapace should be placed at a lower figure than the above. This proposition may be offsetted by the fact that the marginals were not united to each other, and exhibit no indications of contact. ‘The length of seven feet for the cara- pace is not, then, too much, and, estimating from the size of the head, is too 112 little. We.can then safely conclude that the carapace of this turtle is more elongate and narrowed than existing forms. "Thus, in Chelone mydas, the carapace is six-eighths as wide as long. It remains to discuss the question of the age of the specimen. It might be objected that the absence of carapace, and the radiate character of the margins of many of the bones, indicate that our type-specimen is young. To this it may be replied, first, that it is in the (7) sternal bones unlike the young of any known type, when certain of their bodies do at all times exhibit smooth margins as boundaries of the points of exit of the limbs; moreover, it is possible that these plates were dorsal; secondly, the superior or inner extension of the marginals exceeds that of any known tortoise in the adult condition ; thirdly, the articular bone is ossified ; fourthly, separate ribs should be discovered among extinct tortoises as an adult character, on theoretical grounds, the more as it exists in one recent genus (Sphargis, fide Wagler). ; Distribution —This fossil was found near SONG eFOR Wallace, Western Kansas. It was entirely ( recovered by excavating. The edges of one of 71 é the large bony shields were seen projecting from | > a bluff near Butte Creek, and was followed into the chalk-rock with pickax and shovel with the re- sult already indicated. The large bones were ex- posed in an entire condition, but were much frac- tured in the attempt to lift them from their bed. Though carefully packed, the transport of fifteen y/ hundred miles still further injured them, and \ the portions described were reconstructed of Fia.a ‘ : 4 over eight hundred pieces by myself. One of Fig. 3.—Costal bones of ng ° ° mus from below. ane the bony plates was broken into 108 pieces, Testudo polyphemus from below; nat- ural size. the ribs into 183, the marginals into 146, &e. A second species of Protostega' appears to have existed during the Cretaceous period, as indicated by a humerus from near Columbus, Miss., sent by Dr. Spillman to the Academy of Natural Sciences. With it were received bones of the mosasauroid Platecarpus tympaniticus, Cope; and Dr. Leidy, who described them,” regarded all as belonging to one animal. On this basis, he ‘ Proceedings of the American Philosophical Society for 1871, p. 173. * Cretaceous Reptiles of North America, p. 42: Smithsonian Contributions, 1864, 113 expressed the opinion that the fore-limbs of the Pythonomorpha were natatory. That this view was correct I proved by study of the skeleton of Cladasles pro- python; and it now appears that the fore-limbs of the latter were the first ever described. The humerus of the Mississippi Protostega (see Leidy, /. c., Pl. viii, Figs. 1-2) is more elongate than that of the P. gigas, is less contracted medially, and the (great trochanter or) deltoid crest is longer and_ stouter. This I called Protostega tuberosa (Proceedings of the American Philo- sophical Society for 1872, p. 433.) I also pointed out the existence of a third species, as distinguished by the form of the humerus, in the green- sand of New Jersey, which had been referred by Leidy to the “ great Mosasaurus.” From this specimen, Leidy inferred the natatory character of the limbs of Mosasaurus. The New Jersey species I called Protostega neptunia. A name had been already proposed for it; but, as it was unac- companied with specific or generic description, I did not adopt it. This was done in accordance with the well-known rule that such names without descrip- tion are useless in nomenclature; and I conceive it to be not only a privilege but a duty to ignore names put forward in this manner. The custom of giving generic and specific names without corresponding diagnosis has only recently been introduced, and has no claims to respect. It will, if continued, render the science of paleontology accessible only to a priv- ileged class, who may have control of museums, or who can adopt a nomadic life in traveling from one musem to another. In the case of the Protostega nep- tunia, had Professor Leidy, who figured and described the specimen for the first time, adopted the name already given, I should have felt bound to em- ploy the latter, ascribing it to Leidy as the author; but, as he left it among the synonymy of the Mosasauroids, I have thought it advisable to follow him. PYTHONOMORPHA. The characters which distinguish this order are the following: 1. The quadrate bone is attached to the cranium by a ginglymoid articu- lation, admitting of free movement. 2. The ribs are attached by simple articulations to single articular facets oi diapophyses springing from the bodies of the vertebre. 'T inadvertently wrote Platecarpus tuberosus in the above essay. NS) © 114 3. There are two pairs of limbs, which form paddles, having the elements arranged in one plane, and incapable of rotation or flexure on each other. 4. There is no sternum. 5. The scapular arch consists of scapula and coracoid only. 6. There is no sacrum. oe 7. The pelvis consists of slender elements, of which the inferior are nearly transverse, and meet without uniting on the middle line below. 8. The opisthotic bone projects free from the cranium as the suspenso- rium of the quadrate bone, and is supported and embraced by a pedestal pro- jecting from the cranial walls, composed of the prodtic in front and the exoc- cipital behind. 9. The stapes lies in a groove on the posterior’side of this suspensorium, and is produced to the os quadratum. 10. There is no quadrato-jugal arch. 11. The parietal bone is decurved posteriorly, forming the cranial wall in front of the prodtic. 12. The brain-chamber is not ossified in front. 13. The squamosal bone is present, merely forming the posterior part of the zygomatic arch. 14. The mandible is composed of all the elements characteristic of rep- tiles: the articular and surangular distinct; the angular represented by its anterior portion only; and the coronoid present. 15. The atlas consists of a basal and two lateral pieces only ; the odon- toid is distinct, and is bounded by a free hypapophysis, besides the hypapo- physis of the axis. 16. The caudal vertebree support chevron-bones. 17. The teeth possess no true roots. The free quadrate bone and simple costal articulations at once refer this order to the Streptostylicate division of the Reptilia, which embraces only the three orders of Lacertilia, Pythonomorpha, and Ophidia. There are several characters, however, in which it resembles some orders of one other primary group, viz, the Synaptosauria, which embraces the Sauropterygia, Testudi- nata, and Rhynchocephalia.! In the absence of sternum, it resembles tortoises and Plesiosaurs, and differs from lizards. It resembles the tortoises in the ‘See Proceedings of the American Association for the Advancement of Science, vol. XIX, p. 233, 1570. 115 posterior decurvature of the upper portion of the quadrate bone, which thus partially incloses the auricular meatus in a manner not seen in lizards and serpents. 'To the orders of the other primary divisions Ichthyopterygia and Archosauria, as the Ichthyosauride and Crocodilia, there is not the least affinity. The remaining characters above enumerated ally the Pythonomorpha to both serpents and lizards. As there are many Lacertilia without limbs, and some serpents with them, their presence in this order is irrelevant in this comection, especially as the arches supporting them are most like those of tortoises and Plesiosaurs. In the absence of sacrum, it resembles both the associated orders, though the same character is universal in serpents, as the presence of limbs is general in the lizards. ‘The manner in which the opis- thotic bone projects from tie embracing bones is a decidedly ophidian feature, while the production of the exoccipital and prodtic is lacertilian. The posi- tion of the stapes and absence of quadrato-jugal arch are characters common to both orders. The lateral decurvature of the parietal is a character of the Ophidia, and not of the Lacertilia; while the failure of this bone and. the frontal to complete the cranial-chamber in front is a lacertilian feature. The composition of the posterior part of the lower jaw is like that in the lizards in the distinctness of the articular and surangular bones; in the presence of chevrou-bones, it differs from snakes? the atlas and axis are those of both snakes and lizards, and entirely different from those of Crocodilia. In the absence of true roots of the teeth, these animals differ from all Lacertilia, and more nearly resemble, without being identical with, the Ophidia. Thus it is evident that the Mosasauroids and their allies represent an order of reptiles distinct from any other, and I have called it Pythonomorpha, from those points in which it resembles the Ophidia. There are many other characters common to all the known species of this division, which are not probably of ordinal character, and which I pro- ceed to enumerate. Among them will be found some Known elsewhere in the Ophidia, and others which relate them to lacertilian groups. Cranium. The skull, in the known species of this order, is wedge-shaped, and generally elongate. Posteriorly, it presents postfronto-squamosal and parieto- qualrate arches; in some species, also, a malar arch is thought to exist. Tecth—These exist in a single row on the dentary, palatine, and 116 maxillary bones, and in two rows on the premaxiilary. The crowns are simple, and offer various modifications of the cone. Their dentinal substance is confined to the crown, and is attached, at the base, to a pedestal ef ostein, which occupies the alveolus of the jaw, and projects above it. This is stated, by Cuvier, to be an ossification of the tissue surrounding the circu- latory vessels and nerves which penetrate to the crown, and which remain unossified in serpents and most fishes, but are surrounded by true dentinal roots in most vertebrates of the land. Hence, the teeth, in this order, do not possess true roots. The crowns are covered with enamel, and their forms indicate the carnivorous habits of these reptiles. The premazillary is a narrow, simple clement, one-half of a cone anteriorly, and much attenuated posteriorly, separating the maxillaries above by the width of its spine only. Its extremity projects considerably beyond the latter. The anterior extremity bears two teeth on each side in the known species. The mazillary bones are widely separated on the palatal surface, in front, by the vomers; behind, by the nares and palatine bones. They termi- nate in a narrow process behind, whose extremity is broken in the specimens at my disposal, but which may have supported a malar arch, probably slender, as in the dolphins. The nostrils are linear and superior, and separated by a septum composed of codssified nasal and frontal bones. The nares extend to a point in advance of the anterior margin of the orbit. The prefrontals are largely developed, and margin the posterior part of the nares. In many species, their posterior exterior margin projects strongly in the plane of the muzzle, and has caused the orbit to be horizontal, and the range of vision vertical, as in some aquatic serpents; while, in others, it is decuryed, as in land-vertebrates. The frontal is a wedge-shaped, flat bone, and presents lateral descend- ing ale medially. The post-frontals are large, flat, and prominent, and project beyond the process they send, posteriorly, to join the squamosal. Posteriorly, they embrace between them a broad, rectangular process of the parietal, which, in Cizdastes, contains, near its front suture, the parietal fontanelle. In Platecarpus, the foramen is, usually, in or nearer to the suture. The parietal has two broad lateral wings, which advance on the frontal, and form posteriorly the broad anterior margin of the temporal fossa. The parietal crests are separated by a plane which is narrowed, or they unite into 117 a median crest posteriorly. ‘Two antero-superior projections of the supra- occipital embrace the parietal on each side below the crest; while it is over- lapped, just below, by the anterior extremity of the proétic. This does not extend so far forward as the supraoccipital. In front of, and below, this point, the parietal is decurved, and forms a considerable part of the lateral wall of the cranium, though with but moderate antero-posterior extent. The lateral wall extends to the body of the sphenoid, where extensive sutural surface has received it. I can find no suture crossing it; and it is apparently all alisphenoid or all parietal. A part of the parietal is, however, undoubt- edly decurved in front of the alisphenoid. The structure is quite as croco- dilian as ophidian in this point. The postero-lateral angles of the parietal send the parieto-quadrate arches to the opisthotic, which sends an ascending process to meet the parietal, as in lizards. It differs from most of these in the presence of an intermediate bone, which has been observed by Marsh, and which would appear to be a dismemberment of one of those with which it is in contact. The anterior ala of the prodtic overlaps the alisphenoid largely. Its posterior lamina may, or may not, meet the expansion of the exoccipital on the upper face of the suspensorium. Inferiorly, it is in contact with the outer and posterior base of the sphenoid. The supraoccipital is root-shaped. ‘The posterior extremity of the parietal rests upon it, sending lateral arches to the opisthotic, as in most Lacertilia. The exoccipital is distinct, and bears a very small segment of the occipital condyle. The opisthotic stands obliquely upward and forward, and furnishes a glenoid cavity for the articulation of the quadratum. It has a process, directed upward and forward, which occupies a concavity on the inner face of the squamosal, which has the same direction. The squamosal is a subrhombic bone in a vertical plane, and is flat below, and proximally presents a longitudinal external angle; distally, it is slender and prolonged, and receives the posterior process of the post-frontal. The basioccipital presents a strong transverse condyle. It is a massive bone, and presents infero-laterally two powerful processes, which diverge pos- teriorly, and present broad, rugose, ovate faces of insertion. There is an obtuse keel on the middle line below, which bifurcates posteriorly to each 118 of the lateral processes. The distal portions of these processes are over- lapped by corresponding cuplike processes of the basisphenoid. The basisphenoid is distinct from the basieccipital, and underlaps the latter almost to its middle. It is longer than broad, and sends twe processes latero-anteriorly to support the pterygoids. ‘These are not so long as in most lacertilians. Latero-superiorly, it presents a broad surface, on each side of the .brain-case, for support of the upper side-walls. | Postero-cxternally, it supports the prodtic. It thins out anteriorly, and overlaps the alisphenoid. The suture for this bone widens anteriorly; inwardly, it is elevated into a low crest of the sphenoid. The presphenoid appears to have been distinct; its base was small; it is readily lost, and I have not seen it. : The floor of the cranial cavity indicates that the medulla oblongata possessed the downward flexure characteristic of reptiles; but it does not take place till the middle of the length of the basioccipital is reached. The posterior margin of the sphenoid is marked by a deep pit; its median floor is a transverse elevation ; it then descends again, and terminates in a deep longi- tudinal groove. The roof of the brain-case is marked on the parietal bone by two obtuse divergent ridges, which leave its posterior margin and embrace the fontanelle. The grooves for the olfactory pedicels are narrow and well separated, but they unite and are entirely inclosed by inferior processes of the frontal bone, as in serpents and Varani. These ridges then separate, and leave the bulbi exposed below. Behind and between the nares, the median ridge again appears, separating two strong grooves. The vomer is divided, and is composed of two slender compressed bones in contact. The palatine bones have a short lateral union at their anterior end with the maxillaries, and possess a great extension posteriorly, being separated from the quadrates by the short pterygoids only. They ave free on both sides behind the maxillaries, and are flattened cither transversely or vertically, or both, and support a series of strong teeth, generally similar to those of the jaws. Near their posterior extremity, they send outward and forward a strong and generally long process, the distal connection of which is uncertain. These bones are the pterygoids of Cuvier. The true pterygoids are rather short, compressed bones, which are united by suture to the borders of a con- 119 cavity of the palatine. They are toothless, and have no sutural connection with the ossa guadrata. They present no sutural facet for a columella; but Goldfuss and Marsh believe that the latter element exists. I have not seen it. The os quadratum is a stout bone, and one of the most uniformly pre- served among the bones of fossilized individuals. In general, it forms a half- disk; the convex border thin, one side concave, and the posterior border thick- ened. The proximal end is produced backward beyond the line of this border, forming a hooklike process, which is decurved, nearly inclosing the auricular meatus. Just anterior to the latter, on the inner face of the thick- ened portion, is a pit, which received the end of the stapes or stapedial carti- lage. The vertical plane of the inferior or mandibular condyle is oblique to that of the superior. The superior extremity of the os quadratum appears to have had consid- erable motion on the opisthotic. Its extent is so much greater than that of the cotyloid or glenoid cavity, applied to it, as to indicate a gliding motion, especially as if constitutes an extensive arc, possessing grooves of attachment for articular cartilage throughout its length. This arc is bent or curved in the horizontal plane, which would result in a twisting of the os guadratum round its long axis, should the motion I suggest have taken place. Such a twist would throw the proximal portion of the ramus of the jaw outward, a motion quite necessary to the horizontal flexure of the ramus at the splenial articulation, which no doubt took place in swallowing any large object. The extent of this outward deflexion of the articular, coronoid, &e., portions of the jaw, was measured by the outward concavity of the proximal end of the quadratum. hus, this is least in M. depressus, and greater in A. dekayt and M. maximus (see cuts, Fig. 48); the great projection of the external angle in Liodon gave that species an excessive power of dislocation, and the same peculiarity in Clidastes was followed by the same effect. As the development of processes and ridges on the ossa quadrata differ in the different species, they may be named as follows: The proximal articu- lar surface extends over the internaé angle and over the upper edge of the ala, forming the alar process (see plates). Below the meatus and knob, on the postero-external margin, there is a ridge, which terminates in a process in some species, to be called the median posterior ridge. In some, a ridge rises from the outer angle of the distal articular face, extending outside the ridge just> 120 mentioned, toward the pit, called the distal internal longitudinal. In {rout of this, on the inner face of the quadrate, behind or near the origin of the ala, may be a ridge called the internal ridge. (See Plate xxxvii.) ; The cotylus of the mandible is also obliquely transverse ; the inner portion deeper, in order to receive the large condyle of the quadratum The mandible, of ‘course, partakes of the elongate form of the cranium. The fossa for the temporal muscle is large and deep, but without inner wall. The coronoid process is elevated, convex, and rugose interiorly, and with a deep longitudinal groove exteriorly. The superior margin of the coronoid bone is longitudinally concave and obtuse. The dentary terminates in a peculiar striate plug, posterior to the last tooth. The distal third, or less, is strongly grooved for Meckel’s cartilage ; proximally, this is concealed by the very long Jaminiform splenial. The splenial is largely developed on the inner face of the ramus, where it articulates by ball-and-socket joint with the angular. _— The angular has a narrow and inferior exposure on the external face of the ramus, and overlaps the articular by extensive squamosal suture. Interi- orly, it is a little more elevated, but only opposite to the coronoid bone; behind and above this it is restricted by the long anterior process of the surangular. Anteriorly, it is terminated by the squamosal suture of the splenial, just below the beginning of the coronoid bone. The articular furnishes the floor of the cotylus for the quadratum and the large angular termination of the jaw. Inwardly, it is largely exposed; exte- riorly, it is extensively concealed. The surangular is the largest bone behind the dentary. It is convex externally, and sends a longitudinal ridge from the cotyloid cavity to that of the coronoid, thus inclosing a large shallow fossa. It supports the outer or vertical half of the articular cotylus of the mandible. The coronoid is a longitudinal bone attached by squamosal suture only to the surangular. It is easily separated, and its form differs in the genera. It is always more obtuse anteriorly, and more projecting and aliform posteriorly, where its superior margin is rolled over to the outer side. In the splenial articulation, the angular bone presents the condyloid; the splenial, the cotyloid face. The former narrows and retreats upward and backward. The articulation allows of a rotary motion inward and upward; the alveolar margin of the dentary bone being thrown upward and outward. 121 This motion is permitted by the laminar character of the overlapping margins of ‘the splenial, etc., as follows : The principal body of the dentary comes to an obtuse but grooved pos- terior termination. Its external wall is prolonged more posteriorly, the inferior margin fitting a rabbet of the outside of the splenial. The superior margin of this thin plate is much lower than the truncate extremity ; and its margin gradually rises to meet the outer margin of the latter. The section of the splenial is U-shaped, much thickened at the turn. The inner lamina is more elevated than the outer, and is concave, turning outward above to conform to the dentary. A narrow laminar prolongation of the articular is observed be- tween the folds of the U. An outwardly convex, wedge-shaped terminus of the surangular is included between the inner lamina of the coronoid aud the outer lamina of the dentary, moving freely on the latter. There is, then, nothing that prevents this from being a complete articulation, except the lamina of the articular, which is about half a fine in thickness, and probably flexible in life. The superior margin of the coronoid is convex outwardly, and is not con- tinuous with that of the dentary, when the elements forming the splenial articulation are in line. When, however, the process of the articular is properly applied to the dentary, and the coronoid and splenial are in line, as they no doubt were under ordinary circumstances in life, the curvature of the upper margin of the ramus is continuous and normal. At the same time, tle splenial articulation is strongly flexed, and the inferior outline of the ramus angulate at that point. We have in this feature one of the most extraordinary peculiarities of this remarkable order. The mandibular arch, in its usual relations, inclesed a diamond-shaped area, open behind, the portion anterior to the lateral angles the longer, and only closed by ligament in front. The structure is an elemeut of weakness, though, indeed, without such an articulation, such a light and slender jaw would be particularly liable to fracture. There was, no doubt, a strong ligamentous union of the parts, as the grooved adjacent margins testify ; but for any supernumerary muscles to flex the dentary bones I can find no provision. This structure was no doubt designed to effect the deglutition of large bodies, which would readily pass between the expanded mandibular rami. This lateral extension is necessary to reptiles, which, like the snakes, swal- 16 ¢ 122 low large animals whole, but are not furnished at the same time with the arrangement of the suspensorium, the quadrate, and mandible, by which they unfold downward, thus increasing the vertical diameter of the pharyngeal cavity. The palatine and maxillary arches not having the mobility seen in snakes, the mandibles possess increased adaptation to the necessities of doubt- less similar habits. The accompanying cut shows the appearance of the normal flexure of the ramus: ¢ is the splenial articulation; d, the coronoid process; and ¢, the quadrate cotylus. Fic. 4.—Right mandibular ramus of Clidastes propython, Cope, one-third natural size: a, from tho inner side; b, from above. Vig. 5.—Left ramus of Loxocemus bicolor, a pythonid from Central America, inner side, natural size. Vig. 6.—Right ramus of Dryx johnii, Russ., from India, inner side, natural size; 1, articular; 2, surangular; 3, angular; 4, coronoid; 5, splenial; 6, dentary. Vertebra and ribs. Vertebre.—As has heen already pointed out by Cuvier, the vertebrae in Mosasaurus fall into cervical, dorsal, sacro-lumbar, and caudal series. The cervicals are either round or depressed ; they are arbitrarily characterized by the presence of an obtuse hypapophysis, which has an articular surface for a separate continuation of the same. The latter may be compared to short, compressed, ungueal phalanges. The articular extremity of some is nearly plane; of others, conic, with antero-posterior enlargement. They are directed posteriorly, and have a broad, obliquely ovate outline on the lateral view. Their extremities are rugose. The atlas consists of the three pieces, the basal and two lateral. The axis supports a large odontoid process, which is bounded below by a three- sided piece, which is provisionally called its hypapophysis. Besides these, he axis has its own proper fixed and corresponding free hypapophyses. 123 ‘The dorsals have no hypapophysis, and the.diapophyses decrease in ver- tical extent toward the posterior part of the series. The greatest variation is presented by the different species in the long series preceding the caudals, which do not present zygapophyses. he posterior of this series are much shorter than the anterior; the former having the form of the dorsals, the lat- ter of the caudals. In the Mosasaurus dekayi, M. gracilis, and M. giganteus, none of these are depressed; the shorter are subpentagonal in section. In M. depressus and M. missuriensis, the longer are depressed, while the depres- sion of the shorter diminishes regularly to the distal caudal series. In 2. brumbyi, the long vertebre are flattened to a still greater degree. (See Gibbes’ Monograph on Mosasaurus and its allies.) The caudals are divided into three series by Cuvier, viz: those with sep- arate chevron-bones; those where the latter are united to the centrum; and those without them. Passing posteriorly, these vertebrae become gradually shorter and more vertically ovate in form. The more posterior are less nar- rowed in the M. maximus, M. oarthrus, and M. missuriensis (vide Leidy’s work); while, in MZ. dekayi and the Liodons, they are rather more narrowed vertically. The characters of the diapophyses are marked in different parts of the column. In all the species of the family, they descend from an elevated posi- tion on the cervicals and anterior dorsals to an inferior one on the lumbars. They never spring from the neural arch, as in the Archosauria, but always from the base of it. On the median dorsals, they originate from the middle of the side of the centrum, and, on the lumbo-sacrals, from the plane of the inferior surface. They diminish in size, and, as soon as the articulations of the chevron-bones appear, begin to ascend again. On the anterior caudals, they rise to near the middle of the centrum, and gradually disappear at differ- ent points in the different species. The chevron-bones are free throughout the anterior part of the caudal series in the AZ. giganteus, and confluent with the centrum in the posterior portions. This is probably the case with many species of the genus. During immaturity, they may be all distinct in Mosasaurus, while in the genus Liodon (vel Macrosaurus) this condition is permanent throughout life, and thus characteristic. They have two short heemapophysial limbs, and a very long, tapering spine, which is grooved in front. On the middle caudal of certain 124 species it is much longer than the centrum and neural spine, and as long as 4.5 centra adjacent. All the haemal arches are directed obliquely posteriorly. Although I do not possess any specimen with complete vertebral col- umn, an approximate idea of its length may be gained by comparison of parts which are more or less complete in different species. The cervicals are all preserved in a specimen of Clhdastes propython from Alabama, and number eight,’ including atlas and axis. In the type-individual of C. stenops, seven may be counted; in a Platecarpus ictericus, seven; in a Liodon dyspelor, seven; of which the last two are without free hypapophyses, while in the two species preceding, but one without the free hypapophysis is preserved. In Cuvier’s Mosasaurus giganteus, the dorsals number forty-three; in an undetermined Tiodon, from Kansas (alluded to in a former article as Z. datispinus), there are preserved the seven terminal dorsals and thirty-two caudals, with diapoph- yses, which exhibit little diminution in size; the last with stout but reduced diapophysis. Caudals without diapophyses, in a supposed species of Plate- carpus, number twenty-seven ; and there were at least as many, judging from the rate of diminution, beyond these. A specimen of Clidastes vymanii has, according to Marsh, eighty-one with chevron-bones. The rzbs commence at the axis, which bears a small one. There is no distinct parapophysis; hence each rib-head is undivided, but is flattened vertically. The anterior may be known by the greater compression of both head and shaft. The rib of the third vertebra has a narrow, convex, articular surface, and is concave on the anterior face. Those of the dorsals are much wider, and with more truncate head. The limbs and limb-girdles. The limbs in all the members of this order are very small in proportion to the size of the body and tail, and the bones of the scapular and pelvic arches of proportionate small development. The scapula isa broad segment of a disk, differing in form from that seen in any other order of the Reptilia. It only presents facets for the cora- coid and humerus. The coracoid is a similar bone, but embraces a larger ' Professor Marsh (American Journal of Science and Arts, 1872, p. 454) quotes me as assigning ten cervical vertebre with articulated hypapophyses to this species. This I have not done, butstate (Synop- sis of the Extinct Batrachia and Reptiles of North America, p. 221) that it possesses six such vertebriec. Professor Marsh’s statement and consequent supposition that he first determined the number of cervical vertebrae in the genus Clidastes are the result of a misapprehension. portion of a disk. In some genera, it is deeply emarginate, as in Lacertilia; but it is usually entire, as in Sauropterygia. The humerus is a small bone, exceedingly wide in Chdastes and Platc- carpus, and narrower in Liodon. It is wider distally than proximally, has a flat shaft, and presents no condyles, but elongate articular surfaces only. The radius is also a wide bone, especially dilated at its distal and exterior border. The ulna is much less expanded; the extremities being subequal, and the shaft contracted, but flat. The carpals are small, flat, and few in number; they are subround or hexagonal in outline. The phalanges, meta- carpals, and metatarsals are flattened near the carpus, but soon become less expanded and more cylindric at the extremities and at the shaft. The term- inal ones are flat. The pelvic elements are slender, and the inferior but loosely-united on the middle line below. The ilium is the longest, and is quite attenuated above, and without immediate contact with a vertebra. The pubis is clavate and flat; the wider portion next the ilium, and pierced with the foramen observed in Lacertitia. The ischium,is broader, and has an angulate poste- rior outline. The femur is equally or more slender than the humerus (see the plate of Platecarpus crassartus), and, in Liodon, resembles it in form. It is flat, without condyles, wider distally, and with a trochanteric tuberosity at the proximal end. The fibula is a very wide bone, sometimes constituting three-quarters of a disk. The tibia is, like the ulna, a more slender bone than its companion, with contracted shaft, and subequally-exparded extrem- ities. The phalanges much resemble those of marine turtles, and the pes and manus are of a Jess robust type than in any other order of marine reptiles. Affinities. The significance of the ordinal characters has been already pointed out. There remain a number of peculiarities, not certainly of ordinal value, which are, nevertheless, necessary to consider in estimating the relations of these reptiles to others : 1. The form and position of the coronoid bone are those seen in eryci- form serpents. 2. The articulation of the splenial with the angular is only paralleled in the pythonoid and allied serpents. 126 3. The extensive freedom of the palatine is less complete than that of the same element in the Gphidia, and much more so than in most Lacertilia, resembling, in this respect, the Varanide. 4. The close articulation of the parietal with the supraoccipital is seen in the serpents and the amphisbzenian section of the lizards, but not in true lizards; while the supraoccipital crest is a character of serpents, not of lizards or saurians. 5. The presence of fronto-parietal fontanelle is very general in Lacertilia and various extinct saurians, while it is unknown in serpents, crocodiles, and other groups. 6. The parieto-quadrate arch belongs to several groups of saurians and the Lacertilia, but not to serpents. : 7. The squamosal bone has a similar distribution among reptilian orders. 8. The firm attachment of the maxillary to the other bones has the same significance. 9. The want of sutural symphysis is seen in snakes, the varanian lizards, Ichthyosaurus, &c.; but not in Lacertilia generally,- Testudinata, Sauro- plerygia, or Crocodilia. 10. The simple premaxillary is general in the streptostylicate orders, and uncommon in the others. 11. The underarching of the olfactory lobes by frontal lamine is char- acteristic of some lizards (the Varanz) and of all snakes. The above characters are of very unequal value, and may, in many cases, be departed from by forms hereafter discovered without invalidating their ordinal relations with the Mosasauride. As a conclusion, it may be derived that these reptiles are not nearly related to the Varanide@ as has been supposed, but constitute a distinct order of the streptostylicate group; that they are primarily related to the Lacer- tilia, secondarily to the Ophidia, and thirdly to the Sauropterygia ; that they present more points of affinity to the serpents than does any other order; and their nearest point of relationship in the Lacertilia is the Varanide or Thecaglossa. Experience in paleontology has shown that generalized orders have been the predecessors of the special groups of the existing fauna. The structure of the Pythonomorpha, which has so much in common with orders well dis- tinguished from each other, offers a hint of the character of the primary 127% group from which the latter have sprung. That this order is not that unknown type is clear; but the indication of affinity to it is equally unmistakable. Restoration. The proportions and appearance of the Pythonomorpha can be determined from the remains which have been procured. The body-cavity is more elongate than in any group of lizards and saurians, excepting the Amphis- bema, but not so long as in serpents. The tail is excessively long and flattened. The head is also long—in some genera, as Clidastes, very slender, and always flat, with the eyes nearly vertical. There is no distinction between neck and body, but a contraction behind the head. The limbs are very small for the size of the animal, forming broad paddles, with but little peduncle ; the hinder limbs well behind the ribs, and often smaller than the anterior. The general effect of the more slender of these animals was that of gigantic eels, or some of the snakelike lizards of the present time, so that they are veritable sea-serpents of the Cretaceous ocean, and would doubtless be described as such were any perchance to be found to be still in existence in the depths of modern oceans. Several peculiarities affecting the appearance of these animals may be derived from the peculiar articulation of the lower jaws. The position of these articulations in advance of the pharynx indicates a baggy extension of the gular walls, to permit the passage of large bodies between the jaws to the cesophagus. This had, perhaps, the appearance of the posterior part of the pouch of the pelican. This arrangement necessarily requires that the larynx should be, as in the serpents, in the middle or anterior part of the mouth; for, as in those animals, the delay involved in deglutition would cause suffocation were the glottis immediately below the descending mass. This structure requires another, namely, the anterior position of the tongue; and this organ, unless very small, would have to be received into a sheath beneath the larynx and opening anterior to it. Ensheathed tongues, among reptiles, tend to become cylindric in proportion to the completeness of the sheathing, for obvious mechanical reasons. It is almost certain that the Pythonomorpha had tongues of this kind; for their nearest living allies on both sides have them, viz, the serpents and the yaranian or thecagloss lizards. These have the tongue cylindric, ensheathed, and forked at the end, and project it asa delicate tactile organ. 128 It is stated by Professor Marsh that these reptiles possessed scales ; that, in Clidasles, a complex pattern was produced by alternate rows of scutes of different shape and size. They are osseous, but thin, and generally united by beveled edges. Such structures would produce a distinct effect in the living animal. I had already inferred the existence of dermal scales, and figured them in a restoration of Mosasaurus, published in the American Nat- uralist,! but had not suspected osseous scuta. It is a little singular that I have never detected them among the numerous skeletons of these reptiles which I have exhumed in Kansas and elsewhere; nor have any been sent me by Professor Mudge. The proportions varied somewhat in the known genera. Thus, in Clidastes, we see the greatest attenuation of form; while, according to Marsh, the caudal series is less elongate in Liodon. In Clidastes and Platecarpus, the humerus is very short and wide, broader than the femur. In zodon, the humerus is more slender, and not very different in proportions from the femur; hence, the flippers were more distinctly pedunculate. Classification and distribution. The well-distinguished genera of the order known from North American strata are the following : I. Cervical hypapophyses separate, articulating: a, A zygosphenal articulation : Chevron-bones coéssified with centra.-.-.-.-----. Clidastes. Chevron-bones free .32 = 2223224 i eee Stronectes. aa. No zygosphenal articulation : Teeth subeylindric conic; humerus short, platelike ; chevron-bones free-= 3-52 =) += - - see Platecarpus. Teeth mostly compressed, cutting; humerus with nar- rowed extremities; chevron-bones free... ..--- Tiodon. Teeth subcylindrie faceted; chevron-bones in part coossified | Hee es .t2 eo eee Mosasaurus. If. Cervical hypapophyses continuous and entire : No zygosphene asst ee tee. ee Baptosaurus. The material obtained in Kansas, during the autumn of 1871, by the writer, proved conclusively that this order of reptiles attained a predominant 11869, p. 81. 1129 importance during the Niobrara epoch of the Cretaceous period. ‘This is indicated by the great profusion of individual remains and specific forms. Ithough occurring in America, wherever the Cretaceous formation appears, they are, so far, more numerously represented in Kansas than elsewhere. Though not rare in New Jersey, crocodiles and tortoises outnumber them ; but, in Kansas, all other orders are subordinate to the Pythonomorpha. As is now well known, since 1868,' the seas of the American continent were the home of this order; while they were comparatively rare in those of Europe. In the latter country, we have four species only determined by paleontologists, VIZ : JUSTO SANSaNON gS esata ice CoA 3 ee eat eke Om es es Mie 2A he Ce 2 WAKO ANS Reet Sr NPCS Boh ke dP iO AE ae eh A ae ae Re Ae eer GO Saunos poms sees cere emenee See Poi ie ie Foe ens sui Saat mal In North America, the species have been exactly determined from three regicns, as follows: Greensand of New Jersey. Mosasaunisy © = er: SS AA NI OAD eta tena con ee ea 6° | BEN DIMOSTINEY Uist ss 9a ae Su fe acer lee Re a OR fa koe oie een heehee 2 (CNG ESIC SP I Dar ace i I cae NE Ra a eR 2 AOU) are ees Bed th caches C2 LAN eat We NE rome ge MEMOIR ter eONA gate Dupre rey reee eed 4 COD nlo tomo d orieer eee tye y ee) are vane 8 eee eer page Pe copes oy 80S oe 1 15 Rotten limestone, Alabama UU LICOISHIYSEDD a ESHA kek 2 ee gre OO A a ee ieee Ore dogs Ee J BIC Keays ARS) Sy aaa ch ah. a Page Ten! adit oat at py oa uenene eae Po SE RRs Ye, erm, Og MOG OME ae Sah Sr ess ge Te Na ei ceee ushered aca See eM sone MRC Pes 3 Clidastesie: ox = 4:37 GAs Air EW cae e yoy eee nel I Pet ay ra ne A 2 7 Chalk of Kansas. : Clidastess =:3 aes eee seen aia poem aeemr phe Ter TFowi ese Baris! Sep aN 10 SILOMECLESH ae eae meee rE emaE ERITE A TEM an i res OR ee 1 FL ate CE PU Snes ee eee ewes seers ye Yip sc Ne AN RS Abt iciodOm= S55 a2 Spear rey emma npn ONS Ciel SNe A ee 4 1 See Transactions of the American Philosophical Society, vol. XTY. 130 We have additional species from— Northy Carolina; (Mosasaunus\ 422-24 5e se s- 0202 eee il Mississippi (Platecarpus) - - - -- - we hayes a er oars 1 Nebraska (Mosasauntis ie ec. 2 aoe 1 oo, ee ee ee il Making, with the others from— INew Jersey iW ie OU Fade etek See ee 15 AGT Evy ey riya eet ote ER Oa ATE a Se eS hv Bal (Sie SO ee 1 nee ra NET SELS eee se nace cea h shee Foo EP SER EASED at Ee 26 AS total Gf. 28 22 bak ee oe oe 51 Of these, I am not acquainted with any speciés which extends its range into two of the areas above named; while some of these districts possess peculiar genera. It is, nevertheless, premature to draw any conclusions as to geographical range, as most of the species are known as yet from but few specimens. Eistory. The knowledge of the structure of the animals of this order has been due, almost exclusively, to the labors of three paleontologists, viz, Georges Cuvier, Prof. O. C. Marsh, and the writer. Cuvier determined the characters of the dentition, and of the anterior regions of the skull, and of the vertebral column. Professor Goldfuss added little to this beyond the description of the parieto-quadrate and postorbito-malar arches. The writer ascertained the structure of the posterior part of the skull, including the walls of the brain-case, the’suspensorial apparatus, the pterygoid and palatine bones, and the median hinge of the lower jaw; also, of the scapular arch and fore and hind limbs, except the phalanges. On this basis, the determination of the affinities of the order was made. Professor Marsh determined, for the first time, the presence of hind limbs, and described the pelvic arch; he also determined the relations of the phalanges of the fore limb, the presence of two small supernumerary cranial bones, and the probable existence of dermal scuta. CLIDASTES, Cope. Vertebral column exceedingly elongate, the vertebrae united by the zygosphenal as well as the usual articulation; the zygosphene elevated but ea little above the plane of the zygapophyses. Chevron-bones codssified ‘ cervical hypapophyses free. Humerus short and very wide. Parietal fonta- nelle pierced in the parietal bone. The species of this genus are, so far as known, the most elongate in the order. The quadrate bone, in the most typical species, exhibits a very prominent internal longitudinal ridge, indicating a great degree of rotation of that bone, and hence external flexure of the mandibular rami. There are specific differences in the form of the palatine bones in this genus, from the more transverse or expanded type of the C. propython, to that of the C. planifrons, where they are narrowed posteriorly in some degree, to the ©. tortor, where they are vertically placed in the posterior half. Clidastes is nearly allied to Platecarpus, with which Stronectes associates it as an inter- mediate genus. The number of species already known is considerable, and the genus is divided into sections, for convenience of reference : A. Centra of dorsal vertebrae depressed: a. Frontal bones with median keel: CLIDASTES TORTOR, Cope. : A slender species of some thirty feet in length, with a narrow, pointed head of two and a half feet. Its teeth are compressed, and with a cutting- edge fore and aft, and were eighteen in number on the under jaw; the palate was armed with eleven teeth. : The frontal bone is light, and with thin margins; it is keeled above for the anterior three-fourths of its length. On its inferior face, the olfactory groove is closed by the apposition of its lateral bounding ridges. Posterior to this point, the latter diverge and disappear; and a median ridge, with an acute edge on each side, carries the deep median olfactory groove, but disap- pears with the lateral ridges. There is no grooved triangular area in front of the foramen parietale. The parietal bone below presents a V-shaped, rounded ridge; the limbs embracing the narrow and small parietal fontanelle in front. The bene, in general, is bread and expanded laterally. Its antero- lateral ala is largely underlaid by the postfrontal, and presents a transverse ridge for its boundary. The superior surface of the bone presents a flat, longitudinal surface; the angles bordering the temporal toss being obtuse, well separated, and low. Bases of slender parieto-squamosal arches project from it behind. 132 The postfrontal is large and prominent, and terminates in the usual posterior process, connecting with the squamosal. The prefrontal is a slender, flat, triangular bone. Its orbital portion projects at right angles to the orbital margin of the frontals, and is, in its direction, at right angles to the exterior margin. The latter is in the hori- zontal plane, and is transversely plicate. A strong process projects inwardly from the lower side, and is continued across the latter as a curved, flat-topped ridge, to which the maxillary bone is articulated. It soon reaches the outer margin of the prefrontal. ‘The suspensorium is flat (perhaps on account of pressure). The opis- thotic sends a flat process to the parietal. The squamosal is, as usual, a sickle-shaped bone, with a flat extremity for articulation with the opisthotic. Unlike what is observed in Platecarpus and Mosasaurus, it presents no concave articular face below for the articulation (by ginglymus) of the quadrate. Yhe exoccipital extends to near the end of the suspensorium, and terminates in a flat extremity with truncate border. The prodtic, on the other hand, terminates near the middle of the length of the suspensorium by a transverse suture. The basis cranii I have not yet found among the débris of this skeleton. Quadrate bone with long internal angle, and rather thick anterior ala, with broad, rugose margin. A prominent, obtuse ridge is continued from the internal angle to the inferior articular extremity; the distal portion being more acute. A rugose process projects at the point where the posterior hook approaches the body, and is continued, as an elevated, narrow ridge, parallel to the one previously mentioned, to the distal articular surface. A button- like knob appears on the posterior margin of the hook.opposite the meatal pit. A strong ridge extends, on the outer face of the bone, from opposite the end of the hook to the base of the great ala. The distal articular surface presents two planes: the narrower at the end of the posterior pair of ridges above described; the larger considerably less distal, like a broad step. The maxillary bone descends regularly in front, uniting with the premax- illary by minute suture. Its posterior extremity is slender and acute. The premaxillary is short conic; not particularly prominent. The palatine bone has a slight expansion on the inner side; on the outer, the margin is very Harrow. The ¢ceth number seventeen on the maxillary hones. They are com- 133 pressed, least so anteriorly, and with a cutting-edge from base to crown as far as the fifth from the front; in those anterior to that point, the posterior edge is discontinued. There are sixteen palatine teeth, which are smooth, and without anterior cutting-edge. The frontal bone has a low carina along the median line of its anterior portion. Vertebre of the cervical and anterior dorsal regions with round articular faces, not emarginate for the spinal cord. The bodies are elongate and somewhat contracted, and marked everywhere with finer and coarser strie. Hypapophyses prolonged on the cervicals; the free one of the atlas with a prolonged keellike process. Measurements. - Length of the axis with the odontoid process .-.-...----- 22-26 so00 -s 222+ - enon en enee one een ee 0. 078 Miametenoecheyvalleotarcenvaical pverbical yess metaaisyoe cecal see aeates ele eel te leeareniei eine ee pee O026 DiameterotthesballlomtheisamentransversOsecera sale sac loccicieccieceite sae ccticcinetsaeaeeiaee 0. 026 Expanseonphesdiapophyseslombhesamerercacalectsia(emomaleinecinsiee ose oseislsieieee aisaeelaasinse)etaiamen 0. 084 Length of the centrum of the same-..-..--.----------- hee Seite Re brary ERE Se ent 0. 052 iencthroftheymasxiilaryDOn Clem siemelssoecelsceisslessseiesie le lleeae ee Ae Se nee ates pcarsey 0. 363 Length of the ramus mandibuli behind the Gone EFS acer are ee are ennai ety ace eStore paral Sa ators arctan 0.310 Mengthiofthe) premaxillanylesscene ence ciasie ce oscil else ey aa etele oiaedalctay cane aru eetne a iments te terarae 0. 040 hotaljlenothvof thexeranimmy (2:3 teeb)mecreieen shat sce oie seme secisloesicieeiceiaetyene r= Hg Marat a eye Se 0.713 iene thio. thespuerycoideand spalatineeess cee sscisael soe lsiie sees -jaceiseece ce cieeasatsccinee es -iae- 0.315 Length of the centrum of the posterior dorsal vertebra ..---.-...---. +--+. -----+---+-+------+------ 0. 066 Mrametertottheyballywverticales-p- a seston see se eee ace SS HOCECEL COC UE RCOOCE EET RerS 0. 033 Diameteroktheballwtransvierseuass cece ccewie oe sectors sis eas eee som siene eos pee ee mie cer 0, 038 The bones of this species are all light and slender. The elongation of the vertebree indicates that, if their number was of the usual amount, the animal was of more than usually slender proportions. The position in which it was found was a partial coil; the head occupying the inside of a turn of the dorsal vertebree. As compared with L. dispar and E. velox of Marsh, the present differs in the lack of depression of the centra of the vertebrae, especially the anterior, and in some details of structure of the quadrate bones, as well as the larger number of teeth. Discovered in Fossil Spring Cafion, in the gray limestone, by Martin Hartwell and Sergeant William Gardner. But one specimen was found, which includes the greater part of the cranium, with the vertebrae as far as the lumbar region. CLIDASTES STENOPS, Cope. Indicated by a large part of the skeleton of one individual, and fragments of two others. The first includes a large part of the cranium, with both quadrates, and fifty vertebrae, including the axis. The characters are similar 134 to those of the preceding species; but all the bones are more massive, though of the same dimensions. The ¢eeth are strongly compressed with cutting-edge fore and aft, and with the surfaces distinctly faceted; there are seventeen on the mandible. The palatine bones are stouter than in C. dortor, but the teeth are not larger, and are probably as numerous, as they are similarly spaced. The parietal is thicker than in C. tortor, and flat above. The decurved lateral portions are short antero-posteriorly ; behind these, there is a promi- nence on the inferior face, which is broken, but probably ends in the acute median termination of the bone. ‘The apex of an inferior V-shaped ridge is preserved. The parts of the frontal preserved show the olfactory groove nearly closed, and its division in front into two contiguous lateral grooves. The middle of the upper surface is plane; its anterior part, with a low keel. The prefrontal is of peculiar form, and displays the greatest difference from that of C. tortor. Instead of being a horizontal bone, it is so oblique as tu be nearly vertical, From this follows an alteration of the relation of all the parts. The squamosal suture with the frontal, which is marked by pecul- lar concentric rugosities in both species of this genus, instead of being on the upper, is nearly on the under surface, though oblique to both. The lateral margin is subinferior and plicate; the crest of the inner side bounding the maxillary projects far below it in front. In consequence of the form of the bone, there is less expansion of the face in front of the orbits than in other species of the order; whence the face is much narrower, and the name stenops is appropriate. ‘The portions of the prefrontal of the other side which are preserved are similar to those described. The characters of the suspensorium wre in the main as in C. toréor. The quadrates, like those of the last species, have a very prominent internal angle. ‘They present various differences, which may be regarded as ouly individual: for example, the edge of the great ala is not expanded inward, but ouly outward; the distal articular extremity is wider; the poste- riorly decurved hook is more contracted, forming a deeper internal concavity behind the internal angle. The button on the posterior aspect of the hook is wanting; its place being taken by a recurvature of the smooth articular face along the margin. Characters of more importance are, the lack of the two ridges which bound the posterior face of the distal end of the bone, that face being thus convex instead of concave; and the process below the meatus is isolated, and not continued into a ridge, except externally, where it gives rise to the heavy ridge which extends to the base of the great ala. The vertebre exhibit round articular surfaces; those of the dorsal region being rather stouter than the cervical, though the difference does not appear to be so marked as in the preceding species. The anterior caudals possess wide diapophyses. The articular faces are a vertical oval, a little contracted above, sometimes by a straight outline. They preservé a peculiarly elongate form. Measurements. M. Loa LO ETN Ag (IONE) ssedoc cadoo0eso0c0 a656 so60ae Beacon bonads vescos cosouuSibed ed Soumeeee 0. 060 Drametenorthelball pventical eaememee seers eeteescer secre eeee reece eet etieres eee rose ener 0. 027 Diameterorthe ball yhorizontaleeeseremess sees see eee eee eee ee ece rete ree eee ae eee area 0. 027 hen wthvola posteriorly GOTsal soa os aetensae toe eee Sere See oe ee SER hme ree ine aoe emeceaeee 0. 069 Diameterioftheyball vvertical eee saa tecste ere ee See oe eee a ers oe aaa een oe oe ee eee 0. 033 IO TeMaeee OH UK) WAVIL, THARIMENROESO obo Gace Sebo sonooo Landes sede CooUse mooDoD coEUaeDEEd Gone Bedons 0. 033 Wenpthyormtbe.caudaliwithkihefatidiapophysise-seecseesee cesses es steer eeeeerieeee eee eee 0. 033 OHA GPUS CHD CLUS CAWCM) c2ooosebaseac baud beceHeao dads Buns Sebo bebo babu cEoo Bose BeeocSdueS 0.03 Wiidithvofthercupiofethercaudalle seers serch ere ners iane soe see nice sateen cisco ocleene 0. 030 then athvohthermandibles(28ein ches) Peceterrsctseeieeieiniseiciss seaitoeisocirseeisicy see ieieetrsemecisee eet 0.720 Wepihyatulye\ Coronel Ci pLrocessmerrmer emer ences Sree etiam anaes eet leeintario sealers sila 0. 150 Mepibatriuhe: proximalyendiofihercdentanyanesenereroeceeee ee eiee ene eeeeeeaee eae ee eeena 0. 074 Wepibiavichemistaleendombhe.dentaryyrermeieccmiee iss isscoe clase idetsml oes eicsee ce sateen seer 0. 020 A fine specimen of this species was found by Martin V. Hartwell near Fossil Spring; and portions of a second were found by Lieut. James H. Whitten, on a bluff on Butte Creek, during my expedition of 1871. aa. The frontal bone without median keel: CLIDASTES PLANIFRONS, Cope. A large species, represented by large portions of the cranium, including quadrate bone; by cervical and dorsal vertebrae, and fragments of other ele- ments, all belonging to one individual. They are well preserved, and have suffered but little from distortion. The frontal bone is especially massive, and is plane on the superior surface. The superciliary borders are strongly concave, a feature either little or not at all marked in other species known to me. It is thickened; but the fossa for the postfrontal bone extends far toward the front and middle on the inferior surface. In front of the prefrontal angle, the frontal contracts, nar- rowing regularly to the line of the nares. The prefrontal has the remarkable $ form characteristic of Clidastes stenops ; that is, with the exposed face subver- tical or steeply roof-shaped, instead of horizontal. A groove descends on 136 each side to each nareal orifice, and the intervening longitudinal ridge is deeply fissured by a parallel groove. The parietal fontanelle is entirely in the parietal bone. The postfrontal is massive. The quadrate bone presents a very prominent internal angle, as in other Chdastes, and has the posterior hook much prolonged downward and inward, | with a button and surrounding groove on the inner side of one, but none on the other. The stapedial pit is a narrow oval, as in Liodon proriger. The median posterior ridge is prominent, and united with the distal internal longi- tudinal, extending to the narrow posterior angle of the distal articular face. The internal ridge is prominent, dividing the internal face of the bone into two planes, the posterior of which is but little concave along its upper poste- rior border (¢. é., on the inner side of the hook); ‘this region is very concave in some species of the genus. There is a strong transverse obtuse ridge, which extends along the outer side, turning backward into a rough process opposite the origin of the base of the ala. Between this and the distal articular face is a subtriangular rugose area. The palatine bone has its anterior and poste- rior extremities broken away, the fragment supporting six teeth. The bone is flat, much as in the species of Platecarpus, the tooth-line passing from the inner margin behind to the outer before, the roots being more exposed on the external side; the external process is stout. The crowns of the palatine teeth are curved, with lenticular section, one face being much more convex than the other ; the enamel is shallowly striate-grooved. The articular faces of the cervical vertebre are all transversely oval, not much depressed; those of the dorsals are.also transverse, but less so than the cervicals. Jive cervicals and nine dorsals are preserved. ‘The hypapophyses, both fixed and free, are very large and stout. The odontoid is large and prom- inent, and deeper than long. The diapophyses are short, and send a narrowed extension forward to the rim of the cup on all the cervicals and three dorsals. The vertical portion of their surfaces diminishes anteriorly as-the horizontal extends, till, on the axis, it is horizontally subtriangular in outline. The zygosphen is smaller on the anterior than the posterior vertebrae; on the latter, the zygantrum possesses special facets for it. The cups, especially of the dorsals, are emarginate for the neural canal. A smooth band borders the circumference of the ball in front. The surface, in general, is smooth, with rugose lines and grooves extending to the articular face of the fixed hypa- pophysis and apex of the free, and on the upper roof-like surface of the pos- 137 terior zygapophyses. The inferior surfaces of the centra display a more or less prominent longitudinal median ridge. Measurements. ; M. Length of the frontal bone to the nares. .-- <=. --- 2 - nee cewee cece cen cne oececs sarees Seno C606 0.150 Width of the frontal bone posteriorly -.---...---..----. B nad odo ceaade cbacna qaebnenesaToSO50 0565 0. 140 Wadth of theptrontalaboneratibheronDutseesesrr eee nese niceincieacisee incised eteieceleeeieisaeisecie eet 0.104 Wadthvofathetrontalaboneratiuliem aneseee=sseeee see aaa sleseseaeinae esas aciaiseticeels emcee eaieoee 0. 040 Width of the palatine at the third tooth in front of the transverse process>.--..---.---..------- 0. 037 Width of the palatine just behind the transverse process. .----.-..----+ ---226 see eee cece ee tee 0. 035 Mepthjoreshe mand blejatuheycotyl uses seeeer eee ck cease eee namie eee estecises ateaiata = 0. 040 Mepthvofsthespleniall condylevesem meets eaters eterce teeth elelelalsta tetas ers aleeesiote ee ele eieetaisieieke as clesintacere 0. 032 Width of the proximal articular surface of the quadrate (transverse). ....-----.---.------------ 0. 023 Width of the distal articular surface.-... SbodG ac DboS cudcoD Boo SoU SeaoEs Sods cond SoDSeU beso sees 0. 043 Heng thor thethirdicenvically centrale sane seeels= else secs eis) ct= seein sieiae SdcGnd BHSnoo Hobo neSSao 0. 062 Mepuhyjor the; ballvcratheshindicervicaltcentrum=e==aeeecse sae ere eee neee erate ceieee eee 0.030 Width of the ball of the third cervical centrum...-.--..---..-----..----- saeejswe etecenic acs serene 0. 037 Length of the articular end of the fixed hypapophysis ---.--..-- ob BESS nOGe bo COaHEO de onSb60 GobCGS 0. 025 Menothrofathoreeyhypapophysistereseisssseettacoaclec eect meee cece seine stececneee Se eeeee eee 0. 029 Length of a median dorsal centrum..---..-..-.------.-- ome boubed boaouEdoodod Begao poaceenEeeS 0. 072 Width of the ball of a median dorsal aang Soe here seoee til eee ENS Sa esas te ne eee 0. 048 Depth of the ball of a median dorsal centrum ..---.-.----.----2.-2-2---e5-- Sbodsodo cbeces cooEso 0. 040 This species need only be compared with the Cldastes stenops, Cope, which exhibits the same peculiarity of roof-shaped prefrontal bones. ‘That species has the cervical articular faces entirely round; the frontal bone is keeled in the middle, and the palatine much more vertically compressed. The quadrate bone differs in various respects; among others, in the round form of the stapedial pit. As compared with the species described by Pro- fessor Marsh as Mdestosaurus dispar and E. veloz, it differs in the form of the quadrate, which, in these species, is much as in C. ¢ortor and C. stenops; 7. e., with short proximal hook, oblique inferior articular surface, round pit, &e. In this species, the quadrate is truncate distally, &c. This fine species was discovered by the veteran geologist, Prof. B. F. Mudge, during his annual expedition of 1873. AA. Centra of anterior dorsals compressed. CLIDASTES CINERIARUM, Cope. The largest species of this genus as indicated by the zygosphen articu- lation of the vertebree. The region where it was found is the same as the last, but the speci- mens were taken from the gray bed, perhaps the same that produced the Elasnosaurus platyurus, Cope. They consist of vertebrae and pterygoid oy 1G 138 teeth. There are two anterior dorsals, three lumbars, and one caudal. The articular faces of the caudals are broad vertical ovals. They increase in width on the lumbars till, on the last of these, they assume the subpentagonal form characteristic of many species, and which is still more marked on the caudal. The centrum of the anterior dorsal is much compressed ; inferiorly, slightly concave longitudinally, regularly and prominently convex transyersely. Conversely, the rims of the cup and ball are strongly expanded; the latter with surrounding groove. The diapophyses of the lumbars are of consider- able length, exceeding, in this respect, those of Mosasaurus we possess where these parts are preserved. On the median of the lumbars, the inferior sur- face of the centrum first becomes truncate or plane, and separated from that below the diapophyses, which become slightly concave. The expansion of the ball becomes more abrupt and striking on these vertebree. The caudal is a little more compressed than the lumbars, and presents the character of coéssified chevron-bones. These are slender and longitudinally grooved. A single pterygoid tooth was found in the matrix on one of the dorsals The basis is short and much swollen; the crown curved, acute, a little com- pressed, and with an obtuse cutting-edge posteriorly. Measurements. M. Anterior dorsal, length of the centrum..-.-.-..--. ------ ..---.--.- Soitie 2s0s SososscSsy soto SSc¢ 0. 0608 Anterior dorsal, depthiof therarbicnlar Dalits snes scos sees sae lsea= ateece ae ise Sees eee 0.058 Amterioridorsal arid th ofits ax GLOur) corp Ue ea yee at eee eee ee 0. 038 Anterior dorsal, diameter behind the diapophyses ------ ~~ on oa ee eens 0. O29 Anterior dorsal, depth ofthe articular face for the vib ---- -=-- ---- <== = cone eo ne see eee ee ee 0. 022 Lunbar length ofthe: contro). <<< 2. se cems sane esecileeean Os nese cee aacice se ae see aon eee eR eee 0. 060 bumbary depth ofthe: ball o2c2 oe eae. seein cies so mene loe eee eters eee eee eee eee 0. 037 Lumbar, width.-.. -- BESO BECO COROT BODO 2 SSS San mend CSO CCOMOCOCUCIne Saceinans Saat ceceossees Sacic 0. 039 Lumbar, length of the remnantiof the diapophysis -22---2-4- so eee =e ee een eee OL6) bumbar No: 2 lensthiof the centrum 2--2)s---)0 2. =a ie eee ae eee ee 0. 035 bumbar No:.2; width ofthe zyfosphen 22-25. -2-c-6oenens eae ae eee eee eee oe ee eee eee 0. 0182 Cauda) Jenethiof the centrum: ===. --=- <= ---- sa=5 s6- = one = oo een ene ee ee Dee nee eee eee 0, 041 Caudal; depthiof the cup :..5:<.52 -25,-2- Sasa acne coin ens acoso ooeeee An acetone pe ee 0. 040 Gaudal; width-of the cup) -.< 222 sees sae ee A) Caudal; width between the chevron rami =--+----.---- ------ <--5 sss seen ee ae eeee See eee 0. 0115 PRieryeoid tooth: heiehtiofithe ero wn)<--s-s-.sss22-- a2 = <> Sap eee Oe ee eee 0, 0125 Pierycoid tooth, diameter of thepedestall=--- ----=- ----- sees s-o- eee oe ee ee 0. 018 This species was found by Professor Mudge near the locality of the Platecarpus mudgei, six miles south of Sheridan, Kansas. It is only necessary to compare this species with C. intermedius, Leidy, as the C. iguanavus aud C. propython have depressed vertebral centra. Those of the first are rounded; of the present oue, compressed. The C. intermedius ke) also agrees with the two others in the obliquity of the articular faces to the vertical transverse plane of the centrum; in the present species, these planes are parallel. This species is also larger than the C. iguanavus, Cope; the C. intermedius is smaller. A smaller specimen, apparently of this species, was obtained by Profes- sor Mudge during his expedition of 1872. The small distal caudals exhibit the codssified chevron-bones, and the articular faces broader than long; the ante- rior caudals do not exhibit the two angular ridges of the lower side, seen in so many species. The lumbars are short, and the dorsals rather elongate, with the slightly vertically-oval articular faces and contracted sides of the centrum. Measurements (No. 2). M. Length of the centrum (with ball) of the posterior dorsal_-----.-..----<-----------=----------- 0. 060 Mep Fhbotbheycupesy-creeeee cas eye ee eine erste ee Sa ee eee lots araie meja are Ge een eine melons err etoeneraer 0. 042 Wicdthiofetheicuphcsce: sees eso toae sieiie ects sin nee eate aa se be ceed cece ob ieteee ew ebee nde: seeescns 0. 040 enc tliofailum Dare ance acmon scorn itece acces nse eeee een eee eee fu ecie waste ae asiosee Nees 0.040 DEY DUH DOSED ANG) Cay ay a tees ae ses ees ea See Mee et a a as Ra a Ai Ol eet a es ea ee 0. 038 Vian: Ose GHEONI amees ees ene aaa 4 ccs Raton pane Real me eetial NM meats iat SPIRE EAN RUN os em 0. 037 Henethvof the\caudal without) the diapophyses-o-c0-- sees ees sniec= soe ee iecineslsecemle=se=> 0. 021 Wepthyorsth eve presse nets ester sere ete oe arate sarees am ae tee SS 2 Beye MS Oe ei ace els 0. 024 Whidbhiofitheveupinseen srer seen ace oa oem eens wise Sasso ents oi tate Sapo te ers ee Se eal 0. 028 Men cbhvomanmore/distalecaud alte epee eee eree scp Sects ee oe aS eee a eae fe ne isd tee ayes 0.019 Dep Eco iyelerc wp ys sere eae ree ars ete eer gee a oe nke paeasrs ney ek Ne Sree ses atetiaeres 0. 021 WL theo fatheren pi nasreeme tis ciet teva ere aah ee Soe See eee ne aise ao Shem neon ealewe a scewinecess 0. 022 This is the specimen mentioned under the head of Plesiosaurus gulo as having been probably swallowed by the latter. Found near Sheridan, Kans., in the gray shale. SIRONECTES, Cope. The characters of this genus are such as to unite closely that which precedes it with that which follows it in the present enumeration. It is more nearly allied to Platecarpus in the only species known, where the zygosphen is weak, but articulates with special facets on the lateral walls of the zygantrum, which are not known in that genus. The form of the bones of the limbs is unknown. SIRONECTES ANGULIFERUS, Cope. Established on a portion of the left mandible, with a series of thirty-one vertebrae, of a single individual, discovered by Prof. B. F. Mudge in the gray calcareous shale of Trego County, Kansas. Some of the vertebree have suffered from pressure; but the centrum 140 of an anterior cervical is little, or not at all, distorted, as are also many of the caudals. All the dorsals and cervicals have transversely-oval articular faces, openly notched above for the neural canal. The fixed hypapophyses are large; the last one small and subconic, abruptly following a large truncate one. The three succeeding dorsals are keeled below, the Keel of the last low and obtuse. The zygosphen is weak, and deeply notched in the middle. On the anterior cervicals, it is rudimental; but, on the dorsals, supports a well- developed articular facet, which meets a corresponding one of the zygantrum. The fixed hypapophyses and roofs of the posterior zygapophyses are rugose, with grooves and ridges. The articular faces of the caudals are broad, vertical ovals as far as the specimens extend, the series including only a part of those with diapophyses. On the anterior caudals, the chevron-facets are compressed. The neural spines are thinned out in front; obtuse at the base behind, but expanding to a thin edge there also. The sides are longitudinally grooved. Diapophyses on the middles of the sides. Some ribs have the heads not expandad but truncate. The angle of the mandible is produced backward, and below the plane of the lower margin of the ramus, in a marked manner. The lower margin and the surface next the smooth edge are rugose. Measurements. M. Depth of the mandible at the posterior margin of the cotylus .....-...--.---.------.----------- 0. 058 en ethos thercentrumofthelanteriorcervicalss= sss = sae melee a ele ea 0, 070 DiameteriofulewWall Avex ticalcase see elena a= ate eee neal aes ele ee 0, 028 Diameter: of the Nall; transverse: ==... <= -5- eens ene se ac oeee eee ajeanwlese cio see ane eee eee 0. 040 Iuxpanse of thie diapophyses of the anterior cervical ..-...--..---- ..-.--.---=------------------ 05095 Expanseiof thevanterion 2yfapophy ses) sae. eerie ome wane nee ee re eee eee = eee ee eam ORO L Expanse of the diapophyses of the anterior dorsal......-.---.---.---- Si ee 0.115 engthiofitheicentrumiof the anterior dorsalis. -- -)- <= een ene ee come ees ele eet eee 0. 071 Lenoth of thecentrumyof the anterior caudal -2-- oo. «20 eee == eee ee eee eee ee eee eee eee 0. 053 Depthiof the/eupiof the ‘anterior caudal 22-22 <2 aoe ees eae e ae = een ae eee ee eee OAS Widthjof theicuproftheyanterior/caudale 222. --2- soec eae ooo oleae eee eee eee See ee OO aT Width:of the noural spine. 2. -.-2-<--5.s-c6ce- steno nacs coe ~ oceeeene been eee eee eee Ee eee 0. 033 Hlevation: ofthe neural! spine (apex lost)... 2-----c. o--5 ese eee seen eee eoeeeeee eee e eaten oA vacon 0. 021 Length: of the\pterygoid bone. 2232-22 5222s oe ecient eee eee GOS soCC Boon 0.155 This fossil was found by the writer projecting from the side of a bluff in a branch of the Fossil Spring Cation, near the mouth of Fox Cafion. The bluff was from eighty to one hundred feet in height; and the Platecarpus was taken from a position forty feet below the summit, from the yellow chalk. PLATECARPUS IcTERICUS, Cope. Characiers—Internal angle of the os quadratum close by the meatus, and continued as a rounded ridge separating the anterior and posterior internal faces of the bone. Median posterior ridge not prominent. Centra of dorsal ver- tebrae depressed. Humerus broad, short. Description—This species is represented by portions of a cranium, as post- 4 — | P 145 frontal, suspensorial, pterygoid, articular, and quadrate bones; by parts or wholes of several vertebrae, which are all dorsals; and by scapula and cora- coid, with many elements of the fore limb. The latter include humerus, radius, a carpal, and numerous metacarpals and phalanges. The species is first well characterized by the form of the guadrate bone. The specimen lacks a portion of the ala, and the postero-superior decurved pro- cess, but is otherwise perfect. Its form is intermediate between that in Liodon validus, Cope, and Mosasaurus depressus, Cope. Is internal angle of the proximal extremity is posterior to its usual position, as in the former species, but is less prominent than in it. It extends to near the distal end, disappear- ing between the extremities of the median posterior and the distal longitu- dinal angles. The former of these is short, and it disappears by a gradual descent distally in a very rugose margin. The distal longitudinal is short and acute, not prominent at the distal extremity. rom the posterior posi- tion of the proximal internal angle, the alar articular surface is somewhat elongate. The postero-internal face above the meatus is proportionately short. The meatal pit is scarcely one-fifth the usual size, so far as determin- able from the present surface ; but it is possible that the greater part is filled by an impacted mass of bone derived from the adjacent ridge. The margins of the articular extremities and of the ala are striate and papillose rugose. No meatal knob. The suspensorium is slender. It is peculiar in the great extent of the exoccipital element, which covers the whole superior surface, and extends externally over the opisthotic to the squamosal, concealing the former, except its anterior margin. The prodtic sends a small proximal portion only to the superior face. The palatine has been free from its fellow medially. A distal and median portions have been lost; the remaining fragments presents bases and alveole for eleven teeth. The fangs are rugulose and but little swollen ; probably five to seven stood on the lost portions. The bases of the crowns are circular. The external process of the bone is slender and flat. The portion of the mandible preserved includes much of the articular, and adherent parts of the angular. The latter forms a narrow band on the lower edge of the external face, and one twice as wide on the inner face. The only characteristic feature is the lowness of the ridge which descends ME) 146 and extends anteriorly from the anterior margin of the cotylus for the qua- dratum. Of the vertebra, several are so distorted by pressure as to be uncharac- teristic. Two well-preserved anterior dorsals have transversely oval articular surfaces excavated openly above for the neural canal. One is from a position anterior to the other; and these surfaces are less oval, though still transverse. — The centra of both are very concave in profile below, and expand both infe- riorly and laterally to the edge of the cup. A deep groove surrounds the base of the posterior face. In the anterior dorsal, the neural arch is preserved. It exhibits an approach to a zygosphen articulation, more marked than in any other Platecarpus, and is hence nearer Sironectes in this respect, as well as mn the slender pterygoid. A zygosphen is not separated from the zygapophyses, owing to their connection by a lamina of bone. The notches at the posterior end of the arch for this prominence are marked. ‘The neural spine had a jong anterior ala, the base of which extends {o the summit of the neural arch. It presents a fine striation vertical to the centrum and oblique to the edge of the bone, as is seen in C. propython, Cope. The diapophysis on this ver- tebra looks obliquely upward, and carries a vertical articular surface, which is coneave behind. ‘The line of its lower extremity falls the depth of the neural arch below the latter, and of its upper reaches the apex of the canal in front. The more posterior vertebra has, as usual, a broader articular rib-surface, the diapophysis being flattened above and below. The marginal and angular sur- faces are striate-rugose on these and the other vertebrae. One of the free hypapophyses of a cervical is preserved. It has a subtrigonal section, and is longer than wide, and obtuse. Its posterior faces are exceedingly rugose. A cervical rib is compressed and short. Head narrow, large, simple; the adjacent sides striate-rugose. Sides with a shallow groove. The scapular arch is represented by an entire right scapula and proximal! part of right coracoid. The former is broader than in any of the species in which I have seen it, and is flat and thin above. Its anterior extensien is greatest below ; its posterior above, at the superior angle. The lower poste- rior margin is strongly concave and thickened. The antero-superior margin is a regularly convex are of more than 180°. The lower portion in front is on a different plane, and is the rudimental acromion. The articular surface is rugose, and the glenoid cavity not less so. » The proximal portion of the coracoid is flat. It presents the usual fora- 147 men near the anterior margin; and the shorter concavity of the anterior margin leads to the belief that the anterior extremity of the bone is the more pro- longed, as in Clidastes propython. The glenoid cavity is not concave, but merely two adjacent flattened rugose surfaces. Consequently, the humerus has no head, but merely an elongate ‘articular surface, which exhibits a median keel and a short angular expansion near the middle. This bone is of remarkable form, more resembling that I have described in C propython' than any other, and very different from that described in Lodon dyspelor. It is a broad flat bone, expanded at the In the present individual, it is crushed by pressure, so that its thickness is not extremities, and in one plane distally, so as to be as wide as long. readily determinable. Its external surface rises into a crest medially at the narrowest portion, which continues to the lateral angle of the proximal end, following parallel to one of the borders. A moderate thickening exists on the opposite side, a little beyond the extremity of the crest. Strongly rugose striae extend to the edges of the articular faces. An oval rugose muscular insertion exists on the least prominent of the distal angles, and not on a process, as in CL propython. A bone, which, from its analogy to the radius of the last-named species I suppose to be that bone, accompanies the others. It is flat, truncate prox- imally, and with nearly parallel borders on the proximal half. Distally, it is obliquely expanded; the outline forming a segment of an ellipse, whose axis is oblique to that of the bone. Its extremities are rugose-striate. One carpal remains; it is a quinquelaterai bone, one side being marginal and concave. Perhaps it is the intermedial. There are several elements, which are probably metacarpals. The general structure of the whole limb may be determined from these and from the numerous pralanges. ‘The former are flattened and with oblique extremities; the latter more cylindric, with a transverse truncation. Both have a median contraction, which becomes less marked in the distal ones; these are also more cylindric, entirely so at the distal extremities, which are concave, All of these elements are rod-like, much more slender than any of those figured by Cuvier or Leidy. Those immediately following the metacarpals are flattened, but thickened distally. The number of digits cannot be readily determined, but four may be 1See Transactions of the American Philosophical Society, 1869, p 219, Table XIT, lig. 17. 148 certainly distinguished. The general similarity in construction of the manus to that of a cetacean mammal is noteworthy. Measurements. M. Length of the suspensorium anteriorly ----..----. +----------------+-+--+. -+---+ +--+ ------ 0.111 Width of the suspensorium, medially.-.--. .-.------- ----------+---- Bnperoolesoocs ciecso a5onSe 0. 031 Quadrate, greatest length.-..--...----- -------------- +--+ peo 2-2 eee ee ee eee eee ee eee eee ee eee 0. 099 Quadrate, width of the ala...........-------------- DSH Seeech pSeSs0 OAS Somladsae5 SasesobOSSsS 0. 066 Quadrate; thickness behind ------ <2-. 2 2-22 = 2+ = 6 see se nae nse sen sea emacs 0. 030 Quadrate, length of the distal extremity. .----.---.---.- ROE B= 9 2208 GEB20 525 sos sano Ads Sad 0.043 Palatine; length ofisix'alvcoli= ~~. -- -- 2-2 <= seen e eo inin = wenn anni = ome a ae ena a alee eee 0. 055 Anterior dorsal, length of the centrum....-- .------- ---- -- +2 === 225 = ene en en ene =e 0. 059 Auterior dorsal; width of thecup.--- .-- ~~. 5. =~ — 2 = oo em oa me wien = ll 0.0515 Anterioridorsalydeptliof thescup) cee. 1a eet = im lata atalino dla = etalon eset 0. 038 Anterior dorsal, expanse of the posterior zygapophyses ---..--.----------------------. +--+. -2-- 0. 0395 Anterior:dorsal expanse ofa the diapophyses2ae= os 0 seen same ee cole nee te aaa eee setae ee 0. O9L Anterior dorsal }widthvofthemenralicanal (2) =<. fe en naan eispe ene ancl aisle tees 0.0135 Anterior dorsal) depth ofithemeuralicanale= 22. - 26 a aan lien loner ete O SEL Posterior dorsal; depth of the iball ~~~... 2 <2 oo = ane nae a ew wei ene = aye ieee) ON OAD) eee Con, VAahAh Gt Whe Ml = ses soso sesecs soucosd Sse ase pocESD coSdeD ease se sesousedse 0. 0425 Posterioridorsal slenathvofsthexce mtn merits scree era els altace elt ele ale =latelal=telsie re aieee ene ee eer 0. 0585 Posterior dorsal, expanse of the diapophyses -.--.------------------------ ERO pen BORO CoCr 0. 088 Scapula, length ..--...---.-. ooscod onebpaocecots coma sasase cabasapassed sUSaCo Se Scs caso bOCODS 0.145 Bien nu, AND pk dN Ss Gos So ouoossosos eaucaacaccss adercn coSac0 ScecSECeScS0 Sanaa Soshosso 0. 070 Seapula, width, median ...--...---..----- pdoscr ABHSRO SOOO EOS On a sag Do SaS CoSSaNoodton cSaSSES6 0, 112 (Onroad sy ralan, HOI Sees 655 555 opechdosn SocHas GosonSoo sees coeSa5 conan SSosenS SSn000a 0. 066 lafiiMCrEne TaN Ge Sapo. coccoo canbHS bac Sse consoD cetces 4aeSco DaEbES nosecododses Ssda5 cnSs0 HoDC 0.154 LetiENE, GACT, ROR TIE Gon5 scene Sseo.cean cass oend sess bens oseo Bear Soseen yeEcHESocacs CoenSC 0.119 Humerus;iwidth}medianss2 joc aoe oe cone eee ea see ieee ieee a tee eee tes eee eee 0. 075 Humerus, width, distal (restored from C. propython) -------. ----<. - ---< «=o ee «== none ose -- == 0. 158 Radiuswleng thaesecieeeeeteeeiss tar > GES DOA BbSSRde Hoobs Hdd oaeoooSadsagddssSo ddecos pong Ses6 0.115 Radios widths proxim oem eee aciseneeeneiese ieee ete ete ea eine aaten (=a eie ee eee 0. OGL Radinsswidthvdistaly(oblique)maaaceacem es ee cece ee sees ariecminelesieie sete as eneee een eee 0.105 Carpal} lengthisss tno se ona ctatei= Siete aie ie iain epee ere ome te eaten ete ota ote ere aaa 0. 040 Carpal sid tht seco nese eee areas a alae ae ee ee ee ha 0. 037 Metacarpallen g tlicemm= lemme canis eeeios iste setae ein eas lee ate foie ener 0. 095 Metacarpal; width)proximally 22s... ac -=see er eens eeeite esas =a see ee eee eee 0. 045 Metocarpal,-width medially --—-\--- a0 -- scien a mtaee cle oe eieciee © ce niewcleieineinel= see esic eee eee EEE ee ene 0. 018 Metacarpal wid thidistally- << - <2 < sececlesnmiecincon)e ane ee ete a eat nn ne a 0. U34 Phalangrel(medial) Wleneth =< -2- psoccs 2-2 onsen eee le en de ea oe See eee eee Oe eee 0. 08S Phalange) (medial) avidthiproximallyssssssesseeeeene aeeee see eeee decison cage ssmeleiecueeeeeee 0. 027 Phalange(distal), length 2. 2. ..ti sho. sheeted soe ne we ce eee ee ee 0. 059 Phalanrei(distal):vidthidistally;.-; ---.-0-- osce-+ see e.ce ean eee peace eee eee Eee 0, 0082 Ramus mandibuli (depth in front of the cotylus-- 2. ---. .2---. jssces esse en ee eee nee ee 0. 056 Cervicaliribj length. 32. Soeecntttie seo eels secre secs ien ses = os Soke Ree te eee 0.074 The total length of the anterior limb could not have been less than 0".90, which allows of five phalanges in the longest digit. There may have been more. That the digits were of unequal length is indicated by portions of two in matrix accompanying the specimens, where the articulation of two phalanges falls opposite the shaft of one of the adjoining digits. The pha- langes were separated by a short interval of cartilage. 149 The size of this reptile was near that of Liodon validus, perhaps thirty- five to forty feet in length. The specimens on which this species rests were discovered by Prof. B. F. Mudge, formerly State geologist of Kansas, now professor of geology in the State Agricultural College of Kansas, on the north bank of the Smoky Hill River, thirty miles east of Fort Wallace, Kansas. Numerous fragments of another larger individual were found by Professor Mudge near the same locality, which belong probably to the same species. Among them is a portion of the maxillary bone, with bases of two teeth; the bases of the crowns where broken off are not compressed, but slightly oval. A radius is a flat bone, more dilated at one extremity than that of Ciidastes propython. Measurements. M. bene thiofithorading eeces-0 oe eateee eee Seraceee ares Sane om cinioe ine eisiseu sees tec ececsctecoces 0, 108 Widthtoftheradinsjat) themarrowrextremityers mec secon cee caeenocteriece ce -eeees seeereee eres 0. 064 Wiidthyoftethemadinsratithemvyiderestremity, 2o-s)-cce ose eieeicic ene eee ro eee soGo59 6ac0 0. 080 Widthrofsthema dinstmedialliyeyemame cree eee ete eee eee eer ete aeeeiceeeeacccices 0. 042 In addition to the two individuals procured by Prof. B. F. Mudge, the writer obtained a considerable part of a third from a low bluff on Fox Canon, south of Fort Wallace. This includes seventeen lumbar, dorsal, and cervical vertebrae, including axis, with ribs, and a large part of the cranium, with both quadrates, occipital and periotic regions, etc. Its characters may be briefly pointed out as follows: Articular surfaces of dorsal and cervical vertebrae transverse oval, exca- vated above for neural canal; diapophyses not extending below to the edge of the cup, hence not receiving an area of articular cartilage continuous with the rim. Occipital crest low, oblique; quadrate bone larger; the meatus depressed between ridges. A button of articular surface on posterior face of hook. Scarcely any rudiment of zygosphen. ‘Teeth small, much incurved, faceted, and striate-ridged. Some characters, additional to those already derived from the first-known examples, may be added. The mandible supports only twelve teeth. The palatine bone is shorter anterior to the external process, and longer behind it than in H. corypheus. In our specimen, the posterior extremity is broken off, yet shows no indication of the emargination for the pterygoid bone an inch behind the position of its anterior extremity in H. corypheus. There are ten teeth on the part preserved, four in front of transverse process (six in #. coryphaus), and six (probably seven) behind (six in H. corypheus). 150 The plate is more expanded than in the last-named species, especially the thickened inner margin, which only appreaches the basis of the last tooth (reaches the tooth-line at the fifth in H. corypheus). The occipital crest is low, and directed obliquely forward from the foramen magnum. The suspensoria are stout, and directed at an angle of 45° in both the superior and posterior directions. The basisphenoid is strongly keeled below. The quadratum is like that of H. corypheus in its massive external angle and ridge, but differs in the shorter hook and the non-interruption of the groove between the internal angular ridge and the knob below the meatus. The cervical and dorsal vertebre display the same disproportion in size observed in A. coryphaus. Measurements. M. eng thiofthelos quadratumpe-- a) -eeee eae eee eee eater seeeee eee eee eee eee eaeere 0. O81 Width of the articular extremity of the os quadratum............ 2-222 .--2-. -2e2 ee eee eee eee 0. 038 Hens thyo fitheden tary Don eres asaiesmeeies = cise es ekemisiemaieeiseet cinteiseteiaiseiniee ee Sena ee eee eee 0. 280 Length uf the tooth of the dentary bone, third from behind. ........-....--..-----.-----.----. 0, 022 ben's thyoritheitooth;,crownionlyinseneesssaee se ee ee aan sees seiaes aaa see eieeete Eee e neers 0. 016 Length of the suspensorium from the foramen ovale....-.....----..-.--.------ «<=. ------ ==: 0. 108 Totalensgthrofthelcraniumy(23)in ches) saeserc sas eee setae eee eae eee eee Ree ee eee eee 0. 580 This species cannot be confounded with the Lodon proriger, Cope, and L. congrops, Cope, owing to its depressed vertebral centra; from L. mitchillit (=) ) | 5 | ) o] DeKay, the equal and numerous pterygoid teeth separate it at once. PLATECARPUS CURTIROSTRIS, Cope. The specimen below described was found by the writer on the denuded foot of a bluff on the lower part of Fossil Spring Canon. The posterior part of the cranium, with several vertebrae, was found exposed, and many other bones, including the cranial, were found only covered by the superficial washed material. Other portions were exposed on excavating the blue-gray bed of the side of the spur adjoining. The name has reference to the abbre- viation of the head and jaws. These are relatively shorter than in any other species here described where these parts are known. The end of the muzzle does not overhang, but descends gradually to the tooth-line. There are but ten maxillary teeth and two premaxillaries on each side. Size about that of P. corypheus. Characters —Cervical and dorsal vertebrae with transversely oval articular faces, which are little depressed, and, though not continued to the base of the neural arch, are scarcely excavated above for the neural canal. The diapophy- 151 sis with stout inferior horizontal branch, which is capped by an extension of the articular cartilage from the rim of the cup. Occipital crest elevated, sub- vertical. Quadrate broad below; pit sunk between bouading ridges. Description—There is a great disproportion in the sizes-of the cervical and posterior dorsal vertebre ; the centra of the latter are rather more de- pressed than those of the former. They are similar in proportions to those of the other Platecarpi, and shorter than those of the Clidastes. The short axes of the articular faces are subvertical. The rudiment of zygosphen is seen in the slight anterior prolongation of the roof of the neural canal. The keel of the hypapophysis of the atlas is short and obtuse. The greater part of the cranium is preserved. The supraoccipital keel is vertical, and furnished at the summit with a plicate knob for the insertion of a ligamentum nuche. 'Vhe thickness of the walls of the bone is not equal to that in H. corypheus, and the suture for the parietal is a double squamosal; 2. e., with a groove along the middle of the edge. The basisphenoid is but slightly keeled below, and is distally expanded into a horizontal plate on each side. The parietals are, as usual, confluent, and send off two light arches postero- laterally for union with the squamosal bone. Between their origins are two subparallel ridges, which disappear, the transverse section of the narrow part of the parietals being rounded. The lateral ridges within the temporal fossze are obsolete, while the convergent angles which bound the parietal table pos- teriorly are strongly marked. This table is nearly plane, and the foramen parietale is large. The frontal is narrqwed in front, and has an elevated keel along its anterior half. The olfactory groove is not much contracted behind, but is closed by the apex of the rugose area in front of the foramen parietale. The palatine bone is narrow, and the external margin is very slight, the bases of the teeth being exposed in that direction. ‘The inner margin is much thickened downward, but not so as to be a vertical plate. The hinder part of the bone is flat and horizontai, with a long maxillary process. The pterygoid notch falls opposite the second tooth from behind. ‘The whole number of teeth is eleven. The jaes are represented by the greater part of all of the tooth-bearing portions. The maxillary bone is shallowly sulcate on the exterior face. Its proportions are quite similar to those of the HZ. corypheus, but the teeth it supports are larger and fewer. ‘There are none missing from the extremities of the specimen, the whole number being ten; in the H. corypheus, there are eleven. The crowns are incurved, faceted externally, and striate grooved internally ; there are cutting-edges in front and rear, both strongest near the apex; the anterior continued to the base, the posterior wanting on the basal third on the median maxillaries. The anterior vareal excavation marks the fourth tooth from the premaxillary suture. The premazillary bone is remarkable for its shortness and flatness at the extremity; this part being depressed and scarcely projecting at the lower margin in front of the anterior teeth. These, as usual, number four. Both quadrate bones are preserved nearly entire. They have the same general character as those of PZ. ictericus and Pl. corypheus ; resembling rather the latter in the great length of the posterior hook, which is without posterior marginal button. The proximal internal angle.is large and obtuse, and is continued into a prominent thick ridge. The latter divides below, the thick extremity turning outward and ceasing; an acute ridge continuing inward, and joining the interior acute extremity of the distal articular surface. The sub- meatal knob is broad and thick, and not prominent; and its extremity turns at. an acute angle forward on the outer face, and forms the commencement of the great ala. The articular surface is straight crescentic, with an expan- sion on a tuberosity on the inner face (concave of crescent). The meatal pit is sunk between the ridges surrounding, one of which is on the outer margin of the posterior hook. The mandible is nearly perfect. The dentary bone bears thirteen teeth, and, at the extremity, is contracted in both directions, and not prolonged beyond the base of the last tooth. The ridge, which descends from the cotylus along the inner face of the articular bone, is not nearly so strong as in the P. mudger. Measurements. M. Length ofthe axis with thio odontoid - oon en ee ee oe wo iminls einen olor eae ein een 0. 062 Elevation of the neural spine of the odontoid at the middle..-.....-.....-.-...---..----------- 0. 046 enethiofthothird' cervical! (body) \- a= a— ale ma ee ets el eile a eee 0. 050 Diameteriofthe ball) vertical 22 i en oe ene en eee eee le eee eee 0. 025 DinmeteroL theyball horizontal: se. ee eee ee eae ele 0. 032 Length of a posterior dorsal... ---- RSS SE Se BROS a5 So sooaao Sse sso Sass coscapossesdotescosssces 0. 065 Dianeteriofthe) ball; verticals soo. cece an ooo sence elena ale ones eee ete te 0,038 Diameteriof theball horizontal 2 so -o— eae foe = a ee eee eee eee eee eee eee eee 0, 050 ene thiof the basis! erantle=sa-s-—— one name ee eee eee ele eee eee 0, 020 Length of the|SuspensOriam aa 2s sete mn me ela ala eile alle ain ate ae et 0, 105 Elevation ef the occipital crest above the floor of the foramen magnum..-.-.-...-.------------- 0. 045 Lengthiofithe tooth-lineof the palatine=~ ----—- sos. pee oe ae eee ee ee ee 0.115 hength ofthe maxillary bone. -: =). 2455256 oo cane cacce since cone aee nessa ee Pee eee 0.210 Length of the premuxillary Jaterally)-c------- -92-\.=---0lsacle 2 = eee nee ee eee eee ee eee eee 0. 035 At Width of the premaxillary at the second tooth........---.-------. 222. 2222 cee e eens woe eee 0.041 JE eyayeR UN, GSES CANA coco coda coca bose cabo Saco DaoDS soaSed CHS SEO SadoDED aso SEN oESEah HE SasANRoECS 0. 245 IDEA OEM Pay WE Noaso cased 65 cone obce tadSed Se odes cEcd BppasE Hoon Goon ssoesaCo ose cces OL(ET) Length of the:maxillary, tooth, crowmnionlys. 2. 2-s2. = scien wien = ore omen ene ees ween ne nae 0. 023 eng throfuhelos|quadratumeerssaeee eee cee cee eee ieee er ieee ete elena ieee cise aoe 0. 077 Width of the os quadratum distally ---.........--.------.------ «+--+ +----- canbseosod.ccts scodes 0. 045 IDOY AN CHEN JANIE 6456 conc nKesoo code ob06 S08 Sono DobU SHOU de eosuces GosEeaHe Hosa dagecosdceos bles) Length of the frontal to the nares (median)..-.-.--...-..--..----.--.----------- 5 6Q0007 S609 HooC 0.110 Widthyofithefrontalébetweenttherorbitse mars eer eee ae eee ener ene ee tee ererieeeerin Oia) Totallensthvof thercraniumy (18:75 inches) Reseceery seme leet = eter eerste ian tee a= alae leiieeie an! Usd PLATECARPUS CRASSARTUS, Cope. This saurian, which is of larger size than the last, is represented by a series of dorsal, lumbar, and caudal vertebrae, with some bones of the limbs. The vertebree are as much distinguished for their shortness as those of P. latispinis are for their elongation. The articular faces are but little broader than deep, and their planes are slightly oblique. They are very slightly truncate above by the neural canal. The inferior face is somewhat concave in the longitudinal direction. The zygapophyses are stout, and there are no distinct rudiments of zygosphen. The dorsal vertebree best, preserved are those in which the diapophyses reach the middle of the sides of the centra, and have no horizontal limb. The latter are narrow, and have not extensive articular extremi‘al surfaces. The lumbars and anterior caudals have round articular surfaces. One of the latter, with strong diapophyses, but posterior, is subpentagonal in outline of cup. This species furnished the materials for the first description of the posterior extremities in this order of reptiles. The humerus is a remarkable bone, having the outline of that of Clidastes propython, Cope, but is very much stouter, the antero-posterior dimensions of the proximal extremity being greatly enlarged. The long diameters of the two extremities are, in fact, nearly at right angles, instead of in the same plane; and the outline of the proximal is subtriangular, one of the angles being prolonged into a strong deltoid crest on the outer face of the bone, which extends half its length. The inner or posterior distal angle is much produced; while the distal extremity is a flat, slightly-curved, diamond-shaped surface. The fibula is as broad as long and three-quarters of a disk. The phalanges are stout, thick, and depressed, thus differing much from those of Platecarpus ictericus. A bone which I cannot assign to any other position than that of femur has 20 c 154 a peculiar form. It is a stout bone, but more slender than the humerus. The shaft is contracted and subtrilateral in section. The extremities are flattened, expanded in directions transverse to each other; the proximal having, however, a lesser expansion in the plane of the distal end. The former has, therefore, the form of an equilateral spherical triangle; the apex inclosing a lateral fossa, and representing probably the great trochanter. The distal extremity is a transverse and convex oval. This bone is either ulna, femur, or tibia, judging by form alone. Its greater length, as compared with the fibula, forbids its reference to the last; the trochanter-like process of the head is exceedingly unlike any examples of the second bone I have seen. Its reference to femur is confirmed by its presence with the caudal vertebrae of a similar species from near the Missouri River, Nebraska, and its resem- blance to the femur of Liodon dyspelor. Measurements. M. Hens thioftheshumerusyese. seeeece eae else a= oeaee eee ee eee mas een ses se cesenee eerie eee 0.100 - Proximalidiameterioftheyhumerus-screcle= > = eran erie ea eesisin cise emer eae eee ela eeeses 0. 095 Distalidiameteriofthejhum crusts --ee seen eee eine eee eee ee Ce eer ee eee ee ae eee 0. 102 Wen gbhiotsthepteniu tee se erate e a atest ele orale ee ae eee ae 0, 080 Proximal diameterorthorte m Wi esate ol ae eee tole rate alate eee eae ee eee 0. 065 Medianidiameterof they femurseeaosc else ecine soe eisai seeies ee ieee eee else See eee eet 0. 0385 Length of the centrum of a dorsal vertebra without the ball...-......-....---.--.-----:------- 0. 061 iDransverseldiametenor the Cupreese-meeses see oem aan e cane ae eee aerate ears er ee 0. 060 Werticalidiameteroftheicn psa - ase nese ees eee ane eee ee eee ee ee eee eens Se csicees 0. 058 ens thion ag nm bar (total) erate state alee meet ane ee eee eal eee eee ee 0.055 Diameter ofthejballvofia) lumbar! (transverse) nn- =~ <2 eee == een = eee eee ee 0, 060 ene thiotarcaud 1 ues a= see secadbietenescs cuss edsacseseccied sass ese eee eee 0.041 Depthiofsthe) balWofraicamd alee eee lamiain oe ele mlelale ele olel= ese meee alae oleae eee ee eee 0. 052 Widthrof the balliofiaicand alleen eee ese ee foe eines eee eee ee ee eee 0, 052 The form of the humerus is something like that of Jchthyosaurus. Both this element and tlie femur are remarkable for their small size. They are scarcely half the dimensions of the elements of the anterior limb of Plate- carpus ictericus; and are even less than those of L. dyspelor in proportion to the animal’s size Some of the ribs preserved exhibit cylindric shafts. The form of humerus nearly resembles that of P. simus as figured by Professor Marsh, and it is probable that these species are very nearly allied. The vertebrz indicate the largest of species of this genus. The remains above described were obtained by Prof. B. F. Mudge, near Eagle Tail, in Colorado, a few miles west of the line separating that Terri- tory from the State of Kansas. 155 A series of twenty-nine caudal vertebrae, with and without diapophyses, from a bluff on Butte Creek, belongs perhaps to this species. The proximal specimens, at least, cannot be distinguished from those of Professor Mudge’s collection. The distal ones cannet readily be distinguished from those of L. proriger. PLATECARPUS LATISPINIS, Cope. The remains representing this species consist of seven cervical and dorsal vertebrae; five of them being continuous and inclosed in a clay concre- tion. It is a large species, nearly equaling the LZ. mitchzllii in its dimensions, that is, forty or fifty feet in length, and is intermediate between such gigantic forms as Liodon dyspelor and the lesser Platecarp. The type-specimens were found by Prof. B. F. Mudge, one mile southwest of Sheridan, near the “Gypsum Buttes.” These display the elongate character seen in Liodon levis, &e.; but the articular surfaces are transversely oval, thus resembling the P. ictericus. They are less depressed than in L. perlatus and L. dyspelor. The cup and ball of the penultimate cervical are a little more transverse than those of the fourth dorsal, and none of them are excavated above by the neural canal. The last cervical is strongly keeled on the middle line below, and with a short, obtuse hypapophysis marking the beginning of the posterior third of the length; the median line of the first dorsal has an obtuse ridge. There is no keel on the fourth dorsal, but the lower surface is concave in the antero- posterior direction. ‘The diapophyses on the last two cervical and first three dorsal vertebrae have great vertical extent; the articular surface for the rib is not bent at right angles on the first dorsal. Neural arches and spines are well preserved in most of the specimens. There is no trace of zygantrum. The neural spines are flat, and have considerable antero-posterior extent on cervical as well as dorsal vertebrae, and are truncate above. The first dorsal bears a long, strong rib. tok Measurements. M. Transverse diameter of the cup of the penultimate cervical vertebra..--. ...-...-....--------- 0. 051 Vertical diameter of the cup of the penultimate cervical vertebra.........--..-----.-----.---- 0. 041 Length of the centrum of the fourth dorsal, without ball .-...-........-....---.-.s---- .------- 0.072 ViGtii@allabenncuce OF ne Wal ns> ccdcce s6cede noses besebueseted ou ndcededesucg usEaco obeus Se6e 0. 0455 Lransversediameteron tiegballers-ererete eee eee nce nicce Cancers aerator oeaeteeee 0. 0555 Elevation of the front margin of the neural spine of the penultimate cervical.-----....---.---. 0. 088 Antero-posterior diameter of the neural spine of the penultimate cervical.... ..---..----..----. 0. 050 There are smooth bands around the balls, and the surfaces of the centra are striate to these. 156 The depressed cups of the cervicals and anterior dorsals distinguish this species from the Liodon validus, L. proriger, and P. mudgei. The same ele- ments are much larger and more elongate than in P. tctericus. It differs especially from these species of Platecarpus in the elongate form of the ante- rior dorsals. In four of the latter, at least, the inferior limb of the dia- pophysis is turned forward to meet the rim of the cup; while this feature ceases with the last cervical in L. /atispinis. The articular surfaces have planes at right angles to the axis of the centrum, and are not prolonged above, as in P. glandiferus. The last hypapophysis is very short, with the anterior margin transverse and elevated, as in the last-named species. PLATECARPUS GLANDIFERUS, Cope. A smaller species than the last, with apparently a greater flexibility of body, as indicated by the forms of the vertebral centra. It is represented by por- tions of two individuals from localities twenty-five miles apart. There is, unfortunately, in each case, only a cervical vertebra; but they agree in pos- sessing such pecuharities as distinguish them widely from anything yet known to the writer. One is an anterior, the other a posterior cervical. The articular sur- faces are transversely elliptic, and completely rounded above ; that is, neither truncated nor excavated for the neural canal. Their shorter axes are oblique, z. e. make less than a right angle with the long axis of the centrum; and the articular surface of the ball is thus carried forward on the upper face to much nearer the base of the neurapophyses than usual, in the anterior vertebra nearly touching them. The ball is, likewise, more convex than in any other species, having a slight central prominence in the posterior vertebra. There is no annular groove round the ball. In both, the articular surface of the hypapophysis is truncate and bounded by an elevation in front, a peculiarity not observed in any of the species already described There is no trace of zygosphen in either. In the anterior vertebra, the diapophyses are nearly horizontal; the posterior portion slightly thickened and oblique. The ante- rior portion is thinned out, and very rugose above and below, and does not continue its margin into the rim of the cup. In the second vertebra, the dia- pophyses are very large, vertical, and with a horizontal portion rising in a curve to join the middle of the lateral margin of the cup. Neural spine nar- rowed upward, and keeled behind. 157 Measurements. M. Length of the centrum of the anterior vertebra -...----------- +--+ 12+ + eee eee eee eee eee eee eee 0. 064 Diameterortheyballeaverticaleeesemeceeede teeta eter etic site etree een steaeet teem O30 Diameteroftheyballstransversomeen pe eeee sere ae eects eek lee ek sees ener ee eens 0. 039 IDG AN OWN MOSM Socococecocu ce coe 0 baud esed peeG Ones Bae 0500 cose Foeeey caeea™0 See EoeAnoEec 0. 064 Diameterioftheballverticaleereseemeeteee eee sea emer eer ieaias (areas eesti 0. 030 Diameteriofsthey ball horizombalerertscysee epee cstetate a letere eter mteha olen eters etal terel=lai wlel ale = aretel= erate ele linre 0. 043 Hixpanse of the anterior zycapop my Ses ieee terate ee tate alata te steele ale mates le ay loam ae ele noha meal sieleini“i=ie 0. 055 The first vertebra was found by the writer at the foot of a bluff on the lower part of Butte Creek; the second was procured by Prof. B. F. Mudge, from a point one mile southeast of Sheridan, near the North Fork of the Smoky River. It is this species that I compared with the Mosasaurus depressus, Cope, in a report on the collection made by Professor Mudge (Proceedings of the American Philosophical Society, 1871, p. 168). The size is similar, but the form of the articular surfaces of the vertebrae is very different. PLATECARPUS MUDGEI, Cope. The characters distinguishing this saurian are the following: Vertebree without rudimental zygosphen; quadrate bones with plane surfaces from the proximal articular surface and the external obtuse-angled ridge to the meatal pit; the latter, therefore, not sunk in a depression as in the other species. The determination of this species rests on a series of specimens from the yellow chalk at a point six miles south of Sheridan, Kans. They consist of three vertebree and fragments of atlas, with numerous portions of cranium and proximal extremity of scapula. The parts of cranium preserved are the frontal bone without the anterior extremity, and with the adjacent parietal almost complete; parts of the basi- sphenoid; the suspensorium; the ossa quadrata; and the greater part of the surangular. The frontal is flat, with thin edge, longitudinally hollowed on each side of the median line, which is marked by a low but acute keel. There is an abundance of foramina and delicate grooves on the surface, and posteriorly elevated strize, which converge to the median keel. The median square ex- tension of the border of the parietal is in advance of the lateral portion of the same, and not behind it as in Clidastes propython. ‘The fontanelle is large. A marked feature is that the parietal crests unite into a low median ridge a short distance behind the fontanelle, and are not, as in C. prepython, separated by a horizontal plane. The sutures of the bones forming the side of the brain- 158 case are very obscure. Nevertheless, it appears that the descending margin of the parietal does not descend to the front of the alisphenoid, but is mar- gined inferiorly by the latter to the postorbital expansion. No part of the inferior margin of the alisphenoid can have reached the sphenoid, as it ter- minates in a thin edge, except for a short distance medially, where it is broken off. The inferior aspect of the parietal and frontal bones presents a fureate keel corresponding to the divergent parietal crests, and a very large funnel for the epiphysis of the bra. The olfactory groove is deep and regular, and open like that of P. zctericus. The surangular bone is characterized by the prominent longitudinal crest, which descends on the inner side, from the front of the glenoid cavity to below the posterior attachment of the coronoid bone, where it terminates in a thin edge; also, by the short distance between the margin of the glenoid cavity (cotylus) to commencement (or end) of coronoid suture, indicating a shortening of the posterior part. at least, of the cranium. The bone is con- tinued forward only immediately under the coronoid (cfr. P. ictericus). The proximal extremity of the guadrate is characteristic, and exhibits features intermediate between those ot Platecarpus ictericus, Cope, and the typ- ical species of Mosasaurus, as M. fulciatus, M. dekayi, etc. The proximal artic- ular face is much like that of JZ. depressus (Transactions of the American Phi- losophical Society, 1869, p. 181, Fig. 48, No. 3). The internal angle is much smaller than in the Liodons, and more anterior; neyertheless, it is continued distally as a ridgelike angle, separating the antero-lateral from the postero- lateral faces as in them, and not presenting the gradual blending of the two sur- faces characteristic of the genus Mosasaurus. The postero-lateral face is thus flat proximally ; and the meatal pit, which is well developed, cannot be seen from the antero-lateral face. The distal part of the quadrate is lost, so that I cannot determine the character of the ridges there. The basal element of the axis bears a strong hypapophysis without artic- ular faces, but very rugose surfaces The same portion of the atlas is a con- vex parallelopipedon, with median rugose tuberosity and very rugose extrem- ities. Its surface is not separated from its body anteriorly by a deep groove, as in P. ictericus. The articular facets of the scapu/a are much broader than in the other 159 species here described, indicating a head or wider articulation of humerus. No limb-bones are preserved. The vertebrae are too much injured to be characteristic. One posterior dorsal now has a compressed centrum, or, at least, not depressed. The infe- rior face is convex transversely, and there is a slight concavity below each diapophysis; but it is clear that it has been so modified by pressure as to render its normal shape a matter of uncertainty. Measurements. M. IPM, Nema ooso.05e5 cecbosiesdsas saadad Sasbeecdsobeseoose sosose.ouedan condNS Sy cogsed eapccE 0. 074 Parietaljwidthibetwieen the anteriowendsiofitheicrests)2-- 2. 2222 e) seein cle see jie = i lel 0. 048 Ieee ell TEMG WGN 6 cons one bSboon csoSoE KESe Ss Sogdee =EsuEs GQD0e bb EoDD CaScasopbcBR eebaoE 0. 022 In AL TREO AN WANS 666 cosose sooces vousHunouese Geodon eébbnb bounds osased oSEEce sabe asua 0. 092 QWRGhAG, WHEN MOO scocc papoose cdadso coed deco caus KUStea cneoSpaaeUES-AnSE5s HoDodS qosose cage 0. 020 Quadrateslenothifromsthemittomhesproximalven dane peeerses pees e reece eens sree 0. 023 Surangularylenethyofithelowerled em ssemcte eae aires aye BEVEL auc ives spatcicie oe oe 0.015 Surancularadepthvimetrontio fathexcotylispeercrse acter rtl eases cielo sells) el eieieeie 0, 350 Surancolarndepulvatatiexerdo fit bevconom ory erte ete saseeselaininyiaeelale aleres fe rat eleieide reinstates ieeieises 0, 055 1P@SIGHIOE GOH EMMI 5-56 ccbces aed Hebouaenone saScos podoCmoRopemUSbESe oo pee aes seuuceeaUena 0. 0485 Senne. ROSA alba coincooos coss sos ace seecos esuGbU BEES GbaH bo o0ue DnSHES.coBGoD Recsce ceKu 0. 051 This species differs from all those of Mosasaurus and Liodon in which the form of the quadrate is known in the character of that bone. From ZL. levi: and L. congrops, in which that element is unknown, it differs in the stouter or less slender vertebrae; from L. provéger, in its much smaller size. Its size is a little less than the P. ictericus or L. validus. It is dedicated to Professor Mudge in recognition of the valuable results of his investigations as State geologist of Kansas. PLATECARPUS TECTULUS, Cope. Established on a number of cervical and dorsal vertebree of smaller size than those characteristic of the other species of the genus. The centra have no’ suffered from distortion under pressure. ‘Whe articular surfaces are de- pressed transverse-elliptic in outline, with a slight superior excavation for the neural canal, A well-marked constriction surrounds the ball. There is a rudimenta! zygosphen, in the form of an acute ridge, rising fiom the inner basis of the zygapophysis, and uniting with its fellow of the other side, forming a production of the roof of the neural canal, The combined keels become continuous with the anterior acute edge of the neural spine. Thus, the form is quite different from that seen in the previously-described species, and constitutes a lower grade of rudiment. The fact that this zy go- 160 sphenal roof is separated on each side from the zygapophyses by an acute groove gives the former a distinctness more apparent than real. The fixed hypapophyses are short and broad. The centra are not elon- gate. Those of the anterior dorsals present an obtuse keel below. Measurements. M. ene thvofajmedian\ cervical pssseececiecee sees ease eniel = lense ener eae eee reece ietsieiseeete een On O4S Dianieterof the balliofia median cervical, vertical. 22.0. + se elon cies nies ceiieisae ese ceeee eee een O29) Diameter ofthe ball ofa median cervical, transverse .-.--.---. 220-22. oes eee] ceed eee seen eee 0. 033 hen sthiofitheyanterior dorsal see cse.e see =e eae eee eres eee e eee ce iaeen ee eecereeer 0. 042 WAGHINOE BIG) Gl )ese5 5660 s5q5a5 SooD6e. comoue socece JoSoS pepe bocobsbs bss nos asad onbS Seda oSeKaa 0. 082 Found by the author on a low bluff, or “ break,” on Butte Creek, four- teen miles south of Fort Wallace. A second specimen of this saurian has since been discovered by Profes- sor Mudge. The frontal bone is thick, and presents a median keel. The quadrate is flat on the posterior inner face, so that the stapedial pit is exca- vated in a plane surface; the internal proximal angle is nearly right. The vertebree are small, and the hypapophyses short, and with herizontally trun- cate articular faces, as im the type-specimen. This species is the smallest known Platecarpus. LIODON, Owen. Vertebrae without zygosphenal articulation, and with very weak zyga- pophyses; the chevron-bones not codssified to the centra. Teeth with opposite acute edges, compressed, lenticular in section. Humerus small, narrow. The quadrate bone in the known species of this genus is of small pro- portions, and presents a very prominent internal proximal angle and longitud- inal ridge. The structure of the cranial bones is light. The zygapophyses are weaker, and disappear more anteriorly than in any other genus, approach- ing nearest to Mosasaurus in this respect. There are four species of the genus known from the Kansas chalk, all of which have the end of the premaxillary bone protuberant and truncate. A species of similar character has been described by Mr. Hector, from the @re- taceous of New Zealand. Three species from the greensand of New Jersey are similar in many respects; but the forms of their muzzles are unknown. The typical species of this genus (Liodon anceps, Owen) is very little known, but few remains having so far been obtained from the English chalk, 161 its locality and horizon. Numerous North American species resemble it in the forms of the crowns of the teeth, and it is probable, though not certain, that they agree in other respects also. Several names have been proposed for our species, the earliest of which is Macrosawrus, Owen. This name applies to species with compressed dorsal vertebrae, as L. devis and L. mitch- illii, both from the New J ersey greensand. For the species with depressed dorsal vertebrae, as L. validus from New Jersey, L. perlatus from Alabama, and L. proriger from Kansas, the name Nectoportheus was proposed, and briefly characterized (Extinct Batrachian Reptilia of North America, 1870, p. 208). Professor Marsh subsequently gave the Kansas species the name of Rhinosaurus, which name being predccupied more than once, I changed it to Rhamphosourus.' This name will remain for species of the type of L. proriger, if they be found to represent a genus distinct from Vectoportheus or Liodon, of which there is as yet no evidence. Liopon proricER, Cope. The original description of this large Mosasauroid was based on material in the Museum of Comparative Zodlogy, Cambridge, Mass., brought by Prof: Louis Agassiz from the Cretaceous beds in the neighborhood of Monument, Kans., and near the line of the Kansas Pacific Railroad. It consists of the greater part of the muzzle from the orbits, with the right dentary and left pterygoid bones nearly complete; one cervical vertebra (with hypapophysis) ; one dorsal; one caudal with diapophysis; and ten caudals without diapophysis. The characters presented by the vertebral column indicate an exceedingly elongate reptile; the transverse diameter of one of the distal caudal vertebrze is less than one-fifth that of a proximal with short diapophysis; while four consecutive ones of the former show but little variation in dimensions. This diminution amounts to two-sevenths of a transverse diameter of the larger form. With this ratio as a basis, fifty-three two-thirds vertebrae would form a complete series from caudals one-half the diameter of the last of the four to the proximal caudal above mentioned. There have been, no doubt, several caudals in advance of the latter, as the diapophyses are small. From the slow rate of diminution of the columns of other species examined, it may be 1 This name was applied by Fitzinger to two species of lizards which had already received generic nomes, and hence became at once asynonym. Further he did not characterize it. For these reasons, the name was not predccupied at the time I employed it as above; hence there is no necessity for Professor Marsh’s subsequent name Tylosawrus, given on the supposition of predccupation. DM 162 supposed that sixty caudal vertebrae is below rather than above the true number. The cervical and dorsal vertebree have been slightly crushed, as they laid on the side, and present a narrower diameter than is normal; the cup of the cervical has not been distorted, and is deeper than wide, presenting the character of Macrosaurus. The rudimental zygosphen consists of a continu- ation of the roof of the neural canal in front, to adapt itself to the inner face of the down-looking zygapophysis of the preceding vertebra. The latter is thus received into a groove on the inner side of the up-looking posterior zyga- pophysis. The dorsals and catidals exhibit, with the cervicals, that minute, sharply-defined rugosity which characterizes all the projecting margins, especially those of the hypapophyses and diapophyses, in this genus and Ctidastes. The whole surface of the cervical is marked with either inoscu- lating striz or impressed puncte. The same character marks the cranial bones, though they do not present such rugosity as the vertebree. The proximal caudal presents a subhexagonal section, of which the infe- rior and supero-lateral sides are longest; articular faces about as broad as high. A broad, smooth space between the chevron-bones. Diapophyses with broad, ovate transverse section. A caudal without diapophyses, anterior to the middle of the series, esti- mated by the size, is but slightly deeper than long, and with parallel lateral outlines of the articular faces. The neural arch is very much narrowed antero- posteriorly, but has a greater transverse extent at its lowest part; above, the spine is much compressed, but not widened. The zygapophyses remain as rudiments just above the small neural canal, but do not probably touch each other. ‘There are two anterior and two posterior narrow ribs on the upper portion of the neural spine. The more distal caudals have wider neural spines, and the arch has also a greater antero-posterior extent. The zyga- pophyses are scarcely traceable, and the neural spine is strongly striate. The reverse arrangement is observed in Clidastes propython, where the neural spine of the proximal caudal has considerable extent, while those of the pos- terior and distal vertebrae are almost cylindric, especially the neurapophyses. Dimensions. Inches. Dorsal, length--.. ....-..----. ---.----.. -----. Sago SSSR Sapo Se560s 399065 232 4n0 sa5es7 6sS2a5oR52—° 3.25 Dorsal}ewidth oh che CU pHs tes — asa eee lee eee eee ena ele eee ee eee 2.50 Dorsal; depth of the cup)-- << === — semen = wae wen emma nme ne alee ell ole ea 2.77 Proximal caudal, length ,........-..-----.-------- Raocnc Sonne cote 254s sacocosn ort escocccosscs 2.14 a Inches. Proximal, width of the cap. .-< ---- 22. . 2.26 one oe en on nn noe on ene on = eens core ns wane owen 3. 43 Proximal, depth of the cup..---. .----- .--- ---6 e223 = ene ene ne wore ons ee ene ee ene one 3.23 Caudal without the diapophyses, No. 1, length.......---.-...----------.--.----------u--------- 1.6 Candal without the diapophyses, No. 1, depth of the cup ..---------..-------------------------- 2.65 Caudal without the diapophyses, No. 1, width of the cup .-...-...----..----------------.------- 2.6 Caudal without the diapophyses, No. 1, height of the neural canal. .-.-..-.-..-----.----.-------- 0 Caudal without the diapophyses, No. 1, antero-posterior width of the neural spine. ---------.---- 0.8 Caudal without the diapophyses, No. 2, length .......-..-------------- s-.--------.------------- 1.2 Caudal without the diapophyses, No. 2, depth of the cup .......----.---.----------------------- 2.15 Caudal without the diapophyses, No. 2, width of the cup ...-....-.--.--.-.--------.------------ 1.86 Caudal without the diapophyses, No. 2, width of the neural spine (antero-posterior) -.---.-.----- 1.07 Caudal without the diapophyses, distal, length -.-.----.....- ..---- -------.-------------------2 0.5 Cauéal without the diapophyses, distal, depth of the cup..-.-.-.-..---.---.-.-.---------------- 0,85 Caudal without the diapophyses, distal, width of the cup......-.-....-.------------------------ 0.64 Caudal without the diapophyses, distal, antero-posterior diameter of the neural spine-..-.--.-.-. 0.40 The points of attachment of the chevron-bones on the distal vertebree are strongly-marked pits; on the anterior, the anterior margins of the pits are raised and continuous with the chevrons. The muzzle presents the usual characters of the large Mosasauroids, but adds a peculiarity in the prolongation of the premaxillary bone into a cylindric mass, forming an obtuse beak beyond the premaxillary teeth. The bone is narrowed anteriorly, and does not descend regularly, as in Mosasaurus, sp., but continues to its abrupt and narrowed termination described. The extremity is deeper than wide. Immediately in front of and between the anterior premaxillary teeth, a short acuminate projection interrupts the surface, and, in front of this, a transverse depression. Above, the surface becomes flattened, and presents two shallow longitudinal depressions con- tinuous with the nostrils. Where the premaxillary rather suddenly contracts into its spine, it is materially wider than the maxillary on each side of it; in M. missuriensis it is narrower, according to Goldfuss. The maxillary border of the nares is rather suddenly concave at the anterior extremity of the neres, narrowing the maxillaries. The latter gradually widen by the expan- sion of their inner margins. No part of the frontals is preserved, but a considerable part of the left prefrontal remains. It unites by a very coarse, overlapping suture with the maxillary, whose outline forms an irregular chevron, with the apex pointing forward in the middle of the maxillary bone. This, it will be seen, is very different from the form given by Goldfuss in the MZ. missuriensis, where the most anterior point of the suture is on the nareal margin. The external margin of the bone behind, is contracted considerably within the maxillary 164 border previous to its outward extension toward the orbit. This is much less marked in the Clidastes propython, but is distinct in MM. missuriensis. The maxillo-premaxillary suture gradually descends toward the alveolar border, at the extremity of the maxillary bone, where it descends abruptly, forming an interlocking suture quite different from that squamosal type already observed in other species of the order. .The length of the premax- illary anterior to this point is three-fourths the length of the same to the beginning of the nares. The number of teeth on the maxillary bone was probably thirteen ; twelve alveole and bases remain, and I add one in the position of the posterior tooth of M. masswriensis, if such existed. This may be questioned, in consideration of the small number of mandibular: teeth. Premaxillary teeth, two on each side, the anterior with bases separated only by a groove. Throughout the whole series, the bases of the teeth are considerably more exposed on the inner than the outer side. The crowns are everywhere subcytindric at the base; the inner face more convex than the outer. Posteriorly, there is a posterior cutting-ridge, as well as a marked anterior one, both minutely crenulate; but the former gradually disappears till, in the anterior teeth, there is only an anterior edge, the pos- terior face being convex and continuous with the inner. There is a trace of cutting-edge on the outer portion of the extremity of the crown in the most anterior teeth. The anterior ridge remains very strongly marked. The surface is quite rough with longitudinal ribs, of which eight may he counted on the outer aspect of the second maxillary. These are not strongly marked, and are separated by concave facets. The basal part of the crown is marked by numerous fine, sharp strize, which are most distinct on the inner face. The external face of the maxillary bone presents three series of foramina. These rise superiorly on the premaxillary, and increase in number, and become uregular on its extremity. The ramus of the mandible is massive, and differs from that of Mosa- saurus giganteus in continuing its proportions to its extremity. Its depth at the latter point is as great as the sixth tooth from the front. It is prolonged beyond the first tooth in correspondence with the prolongation of the pre- maxillary. This extremity is compressed and obtuse; its inner face is very rugose, as though there had been a closer union at the symphysis than usual, though it would not appear to have been other than ligamentous. The groove 165 for Meckel’s cartilage is very large, and is exposed below the last two teeth, as the splenial terminates at the third. Two series of foramina on the exter- nal face of the ramus. There are alveolee and bases for thirteen teeth on the dentary bone. This, it will be observed, is one more than in MZ. gracilis Owen, and one less than in other species of Mosasaurus. The posterior extremity of the dentary shows its marks of reception into the notch of the coronoid ; it is more compressed and less club-shaped than the corresponding part of L. mitchillii, and would indicate less lateral flexibility than in some other types. The right palatine is of less elongate form than in some other species. It presents the sutural face for union with the maxillary on the outer anterior extremity, and narrows to an apex a little in advance. The dentigerous face is widest at the anterior third of the length, where the outer margin is expanded. This then contracts, and is compressed vertical at the tenth tooth, where it is broken off. The transverse process is given off a little anterior to the ninth tooth. The interior face of the bone is a vertical plane, without projection, except a slight obliquity at the anterior extremity; and it is clear that there has been some interval between this palatine and its fellow. The superior margin is obtusely rounded. The bases of the palatine teeth are exposed for two-thirds their length on the outer side of the bone. The antero-median are large, and the anterior most closely placed. Their crowns are strongly recurved, round in section, and with a fine sculpture of straight strize, most marked near the base and on the inner side. They are more spaced posteriorly than any other species except L. mitchillu, and are relatively larger than in any except the same species. They have not the compressed form with basal shoulder character- istic of the AL. dekayt. Measurements of the muzzle. Tnecbes beng ih ofthe tracm enteeesree eee cetera oteet aiaet eee ser aia ereate ane tetaeyaeracierisincre cis ann ols Length from the end of the muzzle to the prefrontal .........---. .----- .---20----------------- 21.5 Meng th-from:the end of the;mnzzleitojthemmares-s4-.-- se -leoecl tae eee ase cose nse saemr, 11.75 length from’ the endiom themmuzzlestosthemaxallanyee 1-2-2 see neces e cece an = alle 5.73 Length from the end of the muzzle to the first'tooth.-.......---. ..-.-. .--2-06----------- eee ee 2.5 Width of the muzzle at the end --..--...----.----.-- ee See se tenrnts Se aioe aon apes sarees 1.5 Width of the muzzle at the anterior extremity of the nares..---..----. -----. ------------------ 8, Width of the premaxillary at the anterior extremity of the nares ...--..----------------------- 3.3 Width of the maxillary between the tenth and the eleventh tooth....-...----.-----------+----- 3.2 Depth ofthe mandibletatithelextremityaesse- sees ae eae ee ee aeetee ee selec eee ce eA acer 2.5 Wepinortheymandiblejatsthersix tatoo thweeseeees sere. sae sees Se ee ese eae e eee seen 3.5 Depth of the palatine at the transverse DLOCESS teresa aetie Mem eee ee ee tice accesses erscisee = 2.5 1.4 Width of the palatine at the transverse process) -2-- -s2- 5: 5--2-c- cece eoee eeaees cneces ease eos= == Inches. Widthvofiheipal atinennitronters =e aeeeiseecie ee sel seinae lsat aecnn a tne an ecen ieee near 2.2 Length of the palatine anterior to the transverse process ....-.--.------------------++---------- dee Length of the crown of the fifth palatine tooth....-.-.-----..----- .---------+- -----. +--+ ------ 1h Length of the crown of the second maxillary tooth.........----...---..--2-. ------ e222 22 eee 1.9 Diameter of the crown of the second maxillary tooth at the base........----.-----. 2-2-2. .2-- 15 iL The vomers are, as usual, separate and narrow. They are in close contact from the second maxillary to the second premaxillary tooth. Throughout this part of their length, they are embraced by posteriorly-produced vertical lamine of the premaxillary bone. These lamin unite anteriorly just behind the second premaxillary teeth, and form a single prominent keel, which disap- pears between the first premaxillaries. The fine specimen which is the subject of the preceding description was discovered by Colonel Connyngham and Mr. Minor near Monument Station, Kansas, and sent by them to Professor Agassiz. This is the most abundant of the large species of the Kansas chalk. The writer found a muzzle consisting of premaxillary and portions of maxil- lary and dentary bones in the spur of the lower bluffs of Butte Creek, and numerous fragments of cranium and vertebrae on a denuded tract in the same neighborhood. Both of these belonged to individuals of smaller size than the type, the opportunity of examining which I owe to Professor Agassiz. The more complete Butte Creek specimen belongs to a huge animal; the size is grandly displayed by a complete premaxillary bone, with its projecting snout, and large fragments of the maxillary. These furnish characters con- firmatory of those already given as above. The vertebrae are remarkable examples of flattening under pressure, without fracture ; some of them having a vertical diameter no greater than one’s hand. The cervicals are less flat- tened, and give the impression that they were not transversely elliptic. This is consistent with our knowledge of the perfect specimen, where’it is, as described, furnished with vertically ovate articular surfaces. In this, the cup is symmetrical and apparently not distorted, but the ball is a little com- pressed by pressure. The most important addition to the knowledge of this species furnished by the Butte Creek specimen is the character of the quadrate bone. The internal longitudinal angular ridge is very prominent, and extends to the distal end. It supports a hook-like prolongation of the proximal artic- ular surface; almost as large a one as in Clidastes propython, and more nar- 167 rowed. The ridge is so prominent as to create a wider face or surface behind the basis of the great ala than exists between the latter and the edge of the auricular meatus. This basis is quite convex inward, and embraces a relatively smaller space than in any other-Pythonomorph. A section of the bone at the meatus is subtrilateral, with a notch behind. The distal articular surface is prolonged below the origin of the great ala, and receives the keeled termina- tion of the internal ridge. Measurements. ; M. Total leneth of the quadrate .-.......2...----. ------+--6- dagooonU RATE seDkos UOdoadBDUScOCONded 0. 153 Length from the superior to the inferior origin of the great ala. ..---..-..-----2-. .--. +--+ e+e 0. 030 Length of the external angle from the basis of the ala.......-.-.---..-------------+----------- 0. 052 The two usual ridges pass inward and downward from the meatal knob. The above quadrates are flattened from within outward by pressure. A portion of the palatine bone, supporting the teeth, displays the char- acters of the type, viz, the inner face vertical and deeper than the outer, and forming a strong parapet of bone on the superior or toothless aspect ; the outer face a little expanded laterally ; the bases of the teeth exposed. It is proper to add that the locality ascribed to the type-specimen, ‘‘near Fort Hays, Kansas,” which was originally given me on inquiry, is erroneous. LiopoN DYSPELOR, Cope The type-specimen, which first indicated the characters of this species, was obtained from the yellow beds of the Niobrara epoch of the Jornada del Muerto, near Fort McRae, New Mexico. The greater part of the remains have been described by Professor Leidy,' and a few only of the vertebrae came under my inspection. A second specimen, more complete in all respects, was discovered by my party during my expedition from Fort Wallace, Kansas, in 1871, which is fully described and figured in the present work. In the first specimen, the centra of the dorsals are much depressed, quite as in L. perlatus, Cope, and Mosasaurus brumbyi, Gibbes. Their articular faces are of transverse lenticular form, the superior arch being a little more convex than the inferior, and obtusely emarginate for the floor of the neural canal. The superior outline is thus bilobed; the lobes rounded. The trans- verse curvature of the articular ball is quite regular, and not, as in Mosasaurus maximus, more steeply inclined at the external or lateral angles. A rather 1 Report of the United States Geological Survey by Hayden, vol. I, p. 271. 168 broad, smooth band separates the edge of the ball from the surfaces of the centrum adjacent. The latter are rather finely striate-ridged from the edge of this band. The inferior outline of the centrum is strongly concave, and, with two venous foramina, separated by a wide interval. The basis of the diapophysis on a lumbar is very broad, measuring more than half the length of the centrum. In general characters, this lumbar resembles the dorsal, including the emargination for the neural canal, but is shortened in relation to its length. The depressed form of the lumbar centra gives place gradually on the caudals to a more elevated pentagonal outline, which is still more reduced in width in more posterior regions. The heemal arches are articu- lated on the anterior caudals to slightly elevated bases; on the more pos- terior, the bases are reduced in height and more widely and deeply exca- vated. I have not seen the most distal caudals, and hence cannot determine whether their chevron-bones articulate in pits, as is the case with those of L. perlatus, L. proriger, etc. On a caudal, where the depth of the centrum a little exceeds the transverse diameter, the diapophysis has become narrow and thick. The excavation for the neural canal is strongly marked on the more anterior caudal. . The smooth border of the articular ball is here narrow, and the superficial rugze are fine, and confined to the anterior part of the centrum. Measurements. M. ‘Transverse diameter of the ball of the posterior dorsal...-.. ...-2...----- ---0- we enon we ccee oonn 0.144 Vertical diameter of the ball of the posterior dorsal .---...----.------------ ---- Saecosessisecds 0, 097 Vertical diameter ofithe'antenior caudal 222: oe 2 on eerie ee nee nen ae nee eisai aa enee eee enees 0, 094 Transverse: diameter of theranterior canual’ sea. - san see an aaa ae eae oe ee ee ene ee 0. 107 Length of the centrum of the caudal .......--. eS AAD RECORDER SSO RACE eA Ca enOOSoese DeReHa 0.071 Transverse diameter of the neural canal. = ~~ oe oo eens penton se eee eae seem eee see 0.0145 Transverse diameter of the basis of the diapophysis ----~----- .----- --22 e- 2-20 enn mane woe ane 0. 0382 Transverse diameter of the basis of the diapophysis of a more distal caudal............--..-... 0. 0273 Longitudinal diameter of the chevron articulation of the caudal ........-.....-....----------- 0. 023 Hens th ofthe centrum one nae ween es nee es see ae ee 0. 068 Mepth of the'ball of thetcentrum).-.- <- 22.22... 5. sooner cee a oue eee ene e anise Sen ee ee ee 0. 093 Width of the balliof thejcentram =~ << 2 ~ 2-2. soe en np cee anaes seen ee ee eee eee ee eee 0. U9L hength\ of the centrnmiof alumbar..-- ---.5-- = scoces cde sere ea ene e eee eee ee eee 0. 106 ‘Width of the/articulariball-cy.-o- fest a2 enon a= 2h ae casita ener ntcaoe 0,125 The characters of the Fort Wallace saurian are as follows: The fronto-nasal septum is convex in transverse section. The maxillary bone is much attenuated anteriorly, and supports thirteen teeth. The zamus mandibult is light and slender; the angle is quite produced, and the median articulation indicates considerable mobility. The palatine bones are narrower than in any of the species previously described. They are deeply notched 169 for union with the pterygoids, and the superior posterior process terminates in an acute cone. In front of the articulation, the bone is a vertical plate, slightly concave on the inner side; the anterior half is subquadrate in section ; the outer face subvertical; the inner regularly rounded. The inferior surface is marked with a groove which passes from the inner side to the outer. The portion on the outer side of this groove is on the distal third of the bone pro- duced downward into a prominent keel or ridge. The anterior extremity is an acute point. Each bone bears eleven teeth, all of which have the external faces of their roots exposed. The bones are curved outwardly from the fourth tooth from behind; opposite the sixth, there is a longitudinal concavity on the inner face. The occipital region and suspensoria are not present, but both quadrates were found perfectly preserved, excepting the thin ala. They present marked characters, being most nearly allied to those of L. proriger and L. validus. The proximal articular surface exhibits, an obliquity in the transverse direc- tion. It presents a large internal angle, which, instead of being nearly at right angles to the axis of the main portion of the surface, is nearly in the same line. The decurved posterior hook is very short. The distal articular surface has, like that of other Liodons, a small transverse extent, and is divided by a concavity into two tuberosities. The outer of these receives at its angle the prominent narrow portion of the internal ridge, which extends from the internal proximal angle. The prominence of this ridge is greater than in any other species except L. proriger; it is acute throughout its length, and has a gentle sigmoid flexure. - The basis of the great ala includes a smaller area than usual, and is continuous with a prominent narrow ridge, which proceeds from outside the meatal crest. ‘This meatal crest takes the place of the “knob” in such Mosasauri as M. dekayi; it projects strongly backward and outward as an angle of two ridges, the inferior being acute and curved, and terminating above the middle of the distal condyles. The meatal pit is not concealed between ridges, but is internal; its form is peculiar, being a narrow oval, three times as long as wide, directed downward and forward. Thus, the characters of this element are well marked among those pertaining to the other species. The teeth are not much compressed, and have a cutting angle on the anterior and posterior margins, which separate nearly equal faces. The vertebral centra change in form from the anterior to the posterior regions. The ball of the axis is round; those of the vertebrae early succeed - 22 C 170 ing are moderately depressed. The balls of the dorsals are transverse elliptic, with a slight concavity for the veural canal; the plane a little oblique to that of the long axis. The centra are more depressed posteriorly, where the balls of the dorsals present rounded lateral angles. On the lumbars preceding the caudals, the base of the neural canal becomes more elevated, and the articular faces assume a slightly pentagonal outline. This form continues as far as our specimens of caudals extend. On three lumbars, the centra present two longi- tudinal angular ridges below, at whose posterior ends the chevron articular surfaces appear on the first caudals. All present an incised annular marginal groove to the ball. The surface, especially the inferior, is strongly rugose up to this groove, especially on the dorsals. The azis is much shorter than in any other species here noted where known. The neural spine has a very oblique superior margin, and is ex- panded behind. The diapophyses are narrow, and continued as vertical plates to the inferior face of the centrum at its anterior margin. The diapophyses of the other cervicals have the usual horizontal limb, which is, however, shorter than the vertical. In the anterior dorsals, they are directed more obliquely upward, and are longer. These and all other dorsals maintain a connection between the rim of the cup and the anterior basis of the diapo- physis by a smooth area apparently capped by cartilage in life, as exists in P. curtirostris. As we pass posteriorly, these processes descend, and become narrower, until finally they thin out and lengthen into the ribless diapophysis of the lumbars. Those of the caudals are long and subeylindric. Their extremities are deeply striate-grooved. The neural spines of all the vertebrae are longitudinally striate-keeled. The zygapophyses are remarkable for their narrow form and surfaces. The a¢das is shorter on the outer and longer on the inner face than in L. validus. This is caused by the fact that the posterior articular face is not transverse, but very oblique, and, instead of being vertical and narrow, is obliquely longitudinal in its long axis. It is separated from the inner face by a wide rugose groove behind; its lower edge sends a keel downward. There 5 is no process at the thinned infero-anterior angle. The scapular arch is small, especially the scapula, which is absolutely smaller than that of the Platecarpus ictericus, a very much smaller reptile. The posterior margin is thickened, the anterior thinner, and less elevated. The superior ts arched upward and backward. The general form is less 171 oblique than in P. tctericus. 'The coracoid is twice as large, and is flat and thin. Its inner margin is regularly convex; the posterior concave and thin ; the anterior thickened. The foramen is present. The humerus is different in form from that observed in P. crassartus, P. ictericus, Clidastes, &c. It is relatively less expanded proximally and espe- cially distally; there is but one deltoid crest, which is proximal, and near one extremity of the articular surface, and disappears into the general plane above the middle of the shaft. The general form is flat, partly due to pressure. The distal extremity is but little convex, and displays the terminal muscular insertions but little produced. Near the inferior end, there is an external expansion for articulation with the ulna. The radius is lost. The ulna, or a bone which is like that, regarded as such in several species described by me, has the extremities in different planes, which cross each other obliquely. The proximal is triangular and very wide; too wide for the humeri in their present state. It is also too long, leaving but little space for a radius. The distal extremity is as expanded, but much nar- rower, and presents two articular surfaces, a large and wide and a narrow, connected by a wide isthmus. The bone was taken out near a humerus, but not in position. The pelvic arch, as above remarked, was found perfect, and with all the elements present, with a femur with the head in relation with the acetabu- lum. The articular extremities are somewhat depressed, and do not precisely fit. The pubis is a straight, flattened bone, dilated moderately at the proximal articular extremity, where it is pierced by a foramen. It is coarsely rugose- striate at both extremities. The z/ium is a longer bone than the pubis; is more slender, and more expanded at the articular extremity, where it is also thick- ened. The shaft is curved so as to be oblique in position; it shows no trace of union with a vertebra. The zschium is a broader bone, with the axis transverse to that of the body, and sigmoidally curved, first slightly forward, then gently backward. The common suture is about as wide as the proximal extremity. The ante- rior margin is somewhat thickened; the posterior is produced into a short process directed backward, which is the homologue of that seen in the Testu- dinata, and which is connected with the distal end by a thin concave margin. The femur is rather more slender than the humerus; the distal extremity is about as much dilated; the head less so. The great trochanter is a thick 172 convex ridge, with a truncate discoidal articular extremity, which is nearly separated from the head by a groove. Both extremities are moderately con- vex. The fibula is similar to that of other species in its broad three-quarters discoidal form. Both articular extremities are strongly convex, and are con- tinued on the inner side on the thinned inner border. The external margin is thickened and deeply concave, and without tuberosity. The ¢bia is a more slender element, with subcylindric shaft and much expanded extremities. The proximal is oval, and is continued as a narrow ridge on the inner side, for contact with the corresponding ridge of the fibula. The distal extremity is an equilateral spherical triangle, of which the inner angle is on a different plane from the remainder. Tic. 7.—Sketch of the pelvic bones and adjacent vertebra in the relative positions in which they were found on removing the superincumbent rock: 1, ilia; 2, pubes; 3, ischia; 4, femur; 5, posterior lumbar vertebrie. Size much reduced. The phalanges are slender, with cylindric shafis and expanded extremi- ties, which support oval articular surfaces. Those of the two extremities appear to be similar. The distal ones are extremely small and flat, with expanded extremities. Of doubtful bones may be mentioned two with flat expanded distal extrem- ity and thick proximal, bearing an oval articular surface, with an angulate 175 extremity which terminates in a thin edge. The form is like that of a nar- rowed radius of P. zcfericus, but it is much too short for the ulna. As it was found with the scapula, it is probably a portion of the fore-limb, and hence may bea metacarpal.. A somewhat similar but narrower bone may be a meta- tarsal. A piece which is probably the free hypapophysis of the atlas is a transversely elliptic piece, with an oblique smooth articular face at one end, the posterior face rugose, the inferior with a flat truncate process directed downward and backward. If correctly identified, its great peculiarity con- sists in its thinness antero-posteriorly, and the large process. (See Pl. xxxi, fig. 1 d.) In comparing this species with the ZL. proriger, its nearest ally, I have already observed the difference in the form of the articular surfaces of the cer- vical vertebrae, which are in that species vertically oval, in the present trans- versely so. The comparison is made between posterior cervicals of both, which, in L. dyspelor, are less depressed than the others. As it is possible that the form in the type-example of L. proriger may be slightly affected by pressure, I compare other points. ‘Whus, the palatine bones are more slender anteriorly, and the outer edge descends lowest in a ridge; in L. proriger, the inner is produced downward as a longitudinal rib. In this species, there are eleven teeth; in that one, nine. The quadrate bone of L. proriger presents a longer internal angle, and more prominent internal ridge, with smaller space inclosed by the basis of the great ala. My statement, in a published letter to Professor Lesley, that the ends of the mandibles were acute, thus differing from L. proriger, is an error, due to my having inadvertently mistaken the pal- atines for the dentaries while writing. The posterior extremity of these bones in L. proriger is unknown. The only species whose dorsal vertebrae are known to resemble, in the stoutness of their form, those of L. dyspelor is the L. crassartus; the manifold differences of the latter will be at once discovered on reading the description already given. Measurements. M. Atlas, length of the inner articular face:..-..-.-.------------.-.+--2-- SBS EOD GHOOCoORON COGS HONS 0. 065 ‘Atlas; lens thiof the;postenionmanticulantace=-esserstses ose Sce clases sais ecineielsieaiaie em =\nha nine 0. 054 Atlas depbuoraihe;posterioranticularntacepeeee sen ean sane teeetes ease meee cinerea easincen Os 0ad) ARIS leno thiakphermid dle iubhersid emaacrsee set eee er epee orale cialeiais) aelaleaisinieisineleteisiae afaiaisiatats 0. 075 Aisne ppl an Geri Ord yjictee ree ete te erate ore eee ee ae ee enc imic ie ee eee ad Sale netic nintncapesie ee inate ne ermoma 0. 081 ASS, GEV EMOMLGT NS MOTEL IO sss Secoo nocedE Casede baaenS Soncob COBO buco csecSmendos deue Sooe 0. 075 AXIS widtoohbhe neuralispiner(plane)seeeesene seer es eer sac eetsee eels nais saree seeemee sce 0. 045 Axis, diameter of the ball, vertical......... ys es I nN eae Sea tal en er hee RSE 0. 070 174 M. Axis, diameter of the ball, horizontal......-.-...---..---- efeteteteeretaiat= BOS EOaSEoBSoS60 BO G0Ed coSo06 0. 070 Cervical ydiameteriofitheball) verticale =n sseelas= lense see wee nsnl ce aeteneee= eee se eee eee 0. 086 Cenvicaladiameterromthesballshorizon tal essa se aes eee cent a aaa nee 0. 076 Gervicalwlencthhereseseoe teens asia. oe oz af atin tino cetelaclsee cares sel Conse eae ee eae eee eee 0. 090 Anterior dorsal diameter of the ball; vertical. .-- ~~. -- 2-2. ooo on ee ioe oem en acenelon a elena 0. 065 Anterior dorsal diameter of the ball, horizontal... ..---- .--- 22 oo ee cone woe oe eee ete sence 0. 087 Anterior dorsal length below (with the ball) ..--...------..--... BHonssaEoadase coun SosaHSo bees 0. 100 Anterior dorsal Jengthiof thei diapophy sis 2... 22. cce = seen slerinn ain lonl eaten ee ee eee eee see en ON OSG Anteriondorsaldepthiot theidiapophySsis- sss cse—- mene) s~ ae ee einteenaeeieseeieseateeeisine eieisieeanieetasee 0. 040 Bosteriordorsal length of thecentrum: <2 ~~ 2 = ao a ne annie ela ee ela one selena ieeeeie ser 0. 097 Posterior (dorsal diameter of the ball, vertical -- 2-2. 3.55 ooo e emcee lnc een a eee ene ene eee ONOLO iZosteriordorsalydiameterobitheyball whorizontallecrasssneeee cee es a ee caee cence nace eee ene 0. 105 Posterior dorsal height of the neural spine (of another)...--. ..---. .-- 22. 5-222 - wee ene wen ne cane 0. 120 humbar, Jenoth: of the centrom ~~ 2 = 6 ean ole ee en enn (eeneticcoac=s0 055050 0. 030 Lumbar, diameterofthe:ball) verticale = -2= cee ewe ecline = nies se eeeeeeae = see eee eeeneeeeee 0.073 umbaridiameteriof the) ball horizontallo soonest cosleenela--ineoie eee eeise erent reseite eerie eee 0. 090 Tumbar; length of the diapophysis\-- = 2-1 =- -- yaa aime eeriaeneneis a aeese asin eee eecieees 0.096 - Caudali(anterion); lenethtofithe centrum ss = aan eee alam om ae cease enemies ae 0. 073 Caudal (anterior), depth of the ball, horizontal..---.-----...---.- JnOSHOSOUONG RtISSO cqob bend odeo 0. 085 Caudal! (anterior); depth) ofthe ball) vertical ~~ on ee oe enna eee em seen eee 0. 075 Candalli(anterioz); lengthiof the) diapophysis’-----\.-- ose em niece ances seroma sonia ssise el eae nines 0. 120 Caudali(posterion); lens thi of theicentrun te. = cas cecieae aria omnes eerie eta ea eae eaiee ee eae eee 0. 067 Caudal (posterior), length of the diapophysis---------. 2-020 -- 225 22-2 eon nn ence nee eeeeee 05109 @audal/(posterior) height ofithe meural spine = = oon eee annals eonicee eee eee aaeiseteeeeeee 0. 087 Caudal (posterior); diameter ofthe ball, vertical =~ oe eee ene wice none com eecioneeenec ees 0. 080 Caudal (posterior), diameter of the ball, horizontal... .-....--.-.---. 0. ee. -- ooo een ween 0, 084 Were mA, THOM) TEEN, So onsnSs0 shoes dabS cates seat condos sonSas cass noadhs oabe cosas secs os66 0. 650 Maxillary bone, length of the bases of two of the teeth \Goa35) sooo camasU Sageno SoodeC eeeo asad 0. 090 Mandible; depth behind the'cotylus.- ~~ ~~ = en ne ns oi mein ene nom aw eninns ---- 0.110 Mandible; Jenethibehind:theicotylus 228 —m)2m a eee nlmimne elas awe ate ee anes ee 0.110 Width of the nasal septum -- ~~. on we ni wn neem ene sane 0. 021 Length of the palatine on the tooth-line -.-- .-- 2 = ns oon ene woman a wn reaciecenien== 0. 380 Depth of the palatine at the third tooth from the front.-..........-.-----..-.----------------- 0.039 Quadrate, length ~~~. 22-9 a ne oa nn an nw www awww men nnn wns enw eww onan 0.150 Quadrate, length of the proximal internal angle... - ~~~... 2. oe one een nnn w wenn wenn ones 0. 029 Quadrate, width of the face from the meatus to the external ridge -..-...-...-.-. SesdcSaeicoss 0.029 - Quadrate, width of the area of the basis of the ala ..--..--...----. -.-- -----2-- 2-20 ----nn-e---- 0.040 Quadrate; width) at theicond Wles en mene. (oneal er een aeniee eens e eee ene eee ee eee 0. 07 Scapula, herehti (axial) eee cee e eee eee meme einem ale nin ale ieee aessoreo sa5- 0. 120 Scapula, wid thyme ne aa ee la annian alae ele ale aes eee eee ae ee 0, 183 Coracoid) width).<2 =< 3<)sccce. on ncnn cacb ce sue euap me oe nlen ness anene ele en Sane oee eee eee 0.187 Coracoid len rhe nate me eae tne 0. 200 Coracoid;thickness/atithecotylus\---- - onc. ocmanjenenine === =len eon /a one ia=aelenee eens eee ee eee 0. 027 Humerus, length .-.......-- ESSN O SIU Soe EOE Pos baeo pooSss scecsas hace cess Son sops dsotacss 0.189 ameros; prosimaliwidth ss ce. -o- == coe) aoa melon em eee mae = aaa nts one ee en ee 0. 120 PANMETUS, CIStal Wid thiscecn—=-\emeoi= ao nene = enn nineisenel eens aa ee eee ee eee = ee eee 0.127 Wi VEN ANY oho cose SSeS SSO SSSI DES HOO ASS DSR O ERD BECO OAS SEAS HOSE BES COCs Saoso Heao ses 0.179 nas width proxd Mallen. someon. camcaclien=aclee= cee ese so nla ee ee 0,115 (lnas width distal os ence cnn mie neem enone cic scree sa secc eee come e ne en eee 0.116 Ulna, thickness proximally ; Pubis; length. ooo nen re nn nn oe wer peer leeee eee Pnbis;widthy proxi Malena es. eee ee ine ele a ae a ee ee IPODS wid eh O18 Gale ee ele a nln eal an ee eee Tlium, length on the curve Ilium, width, proximal *........-..----.---.---.---- a mm nw mee penne ween sa nanlaae aotcese 0. 018 Mm wid thy CuStal ae n= = em ieee ete ate al la ol 0. 087 Tschium lenrth) (Straight) =~ <2 - -aeeeeleeeeleie ee cen ne enina ene SaaS aaae SaaS esSnee {02522252 0.195 Ischium, length to the posterior process (axial)......... pdsbos meaoosd 255 BRAdacen0 sal se20e 3053 0.125 M TREeTS WGN, ROEM 56 co00 sooo0s Soeocs Sasene doses sadeaS Bess Boag SogecOnRbSES GO=E86 s80eS5 0. 085 TRAE, wae n, GNC ono. co50' Shan cocece cposesedesHH cond BaaGeD sHbo sdedon seadoass ecb pHae See 0. 075 IDS NTR MONI Saas dacs co50 Sado coaceo Sodoae Geccgs cece cero coos saDcES sooEES cHaD coTonoes ceco ceac 0.185 TREATS, Wendt, PORTA | oS c0 Reeds Sads G000sh S60G0e 6550 05600550 6600 op OSD Cone co cose nes 6505 0. 093 IDE EMOTE, WAN THETA 5 Soca taeda node Sasq CaCe50' 600 2506 BOE RUDIaSHCOH SDSO Kec aeHD OnDDbS6 SDE 560 0. 064 Idea, WAGON, CHEM oo CosSe6 oooe Hone ado0. bado SnSUOO ROOSEE HacGos BaDESO Suen EON nODocS HO0n an55 C050 13 IPM, WED No= osc0n05 co00 poc0 DooG Soese Sooo DUdaDONS BoagGepe DoDa dodo beds SoUS bogEEeecasaanSos Mibulaswid th eprosim a lesemterterelaetieisekeeekseineenieatsorcrtetsscctescietismceieinaieciseiessiekese ele tekeraita Eibulaswadth dis taleaccrsceatecteictsciatcetecterseccrcictelsiciencistcle meienciete tet tesiore ciate elec increleicie craiereisialcie's Hibulayproximalechiclknesseeceeteresetectetecertescer sale cise etlieteeieeicetecise eleisicieetaete teeioe esate Mibulo, median iwidthe ses cecscssce setters cere clscte se see a aronin cise elriave win otelnvwlejelajere ia etosyseiscvaielarsis AUDI Hemet oro ear dood Seeds Ga cone uA So eat Soo udaOSdonE ad dda coun nese co ou ba eoedab Da SUSenoae ossesssssese S @ (=) Tibia; width; proximal sesles Ss incjsareeele eset iseise Salem eons oelociaaloe elle ciclo wie cicciemiaseiectos cease sei’ 045 Abia. widbthsmedian's: she. = <2 seek. peer eee ape twar tee setae eicinin ayant Satecve ce osisleloereate siesjacieeis = 025 PRED Ias swat nis tals saeco aerate On aete eae ee are eee ae ne ein ean pe oho ay ASS ee, VOTES esa Ok 052 Tibia, thickness, proximal..--.. -.-- eee wroatctein wis sibiae owuse nis elepsseieee Hoeais wisisieeeiein cferercin cle saree 042 ibis thickness distalgeseee is ceerserects DAS Roa ete eee ays Des Aeieee calce som teciete ereiceee 6. 030 Bhalangel(posterion) len bhp meres eyeeeeiseieeecieereeiee ste eee eee sae sale ets eeeeee 0. 080 halangequerminal wen mb hweerepaceseeeererencsaceaacecian esem came terseeemaiemeeraecee sciences 0.015 This specimen is one of the most instructive which has yet been dis- covered, including, as it does, fifty vertebree from all parts of the column, a large part of the cranium, with teeth, and both quadrate bones; the scapular arch complete, except back of coracoid on one side; both humeri, radius, and numerous phalanges of fore limb; the pelvic arch complete, with one hind limb complete to tarsus, with phalanges. The premaxillary is wanting, but the adjacent suture of the maxillary remains. Portions of a second individual of this species, or of L. proriger, were found on the Fox Canon. They belonged to a larger animal, one equal to the New Mexican first described. Professor Mudge has fragments of still larger specimens. The principal specimen above described was excavated from a chalk bluff. Fragments of the jaws were seen lying on the slope, and other por- tions entered the shale. On being followed, a part of the cranium was taken from beneath the roots of a bush, and the vertebree and limb-bones were found farther in. The vertebral series extended parallel with the outcrop of the beds, and finally turned into the hill, and was followed so far as time would permit. It was abandoned at the anterior caudal vertebre. The outcrop of the stratum was light-yellow. The concealed part of the bed was bluish. Yellow chalk left on the specimens in thin layers became a white, or nearly so. The yellow and blue strata are definitely related in most localities, the former beimg the superior; but in others they pass into each other on the same horizon. In instituting a comparison between this and other known Mosasauride, 176 it will be necessary to consider species referred to Mosasaurus as well as to Liodon, from the fact that some of the former may really be Liodons. The Liodons with compressed or round dorsal or lumbar vertebree may be dis- missed from comparison. Of the depressed species, L. perlatus, Cope, is known from specimens of one-third or less the size of the present one, which are further peculiar in having the diapophyses of the lumbars to stand on the anterior half only of the centrum. Among Mosasauri with depressed vertebral centra, it is to be noted that none present so great a degree of depression and lateral extension except the M. brumbyi of Gibbes. They are all also much smaller. The M. brumbyt was founded by Dr. Gibbes on two lumbar vertebree from the Cretaceous of Alabama, which resemble those of the Af. dyspelor in form, and also in size. It is probably its nearest ally, and may be a Liodon. Dr. Gibbes established the genus Amphorosteus for it, but without sufficient evidence to support it. The principal point of distinction between it and the L. dyspelor which I observe is the lack, in the former, of the strong emargination of the superior margin of the articular surface for the floor of the neural canal, which is so marked in the latter. I have only the figures of Gibbes to rely on for this particular, and it is scarcely probable that the artist would have overlooked it had it existed. Should the bounding prominences have been worn off, then the restored centrum would have had a notably greater vertical diameter than in the Z. dyspelor in the same portions of the vertebra! column. Asa second character, I note that, relying as before on Gibbes’s figures, the external angles of the depressed ball are not so extended laterally in JL brumbyt. In size, the vertebrae of the present animal exceed those of the M. brumbyz. The latter has been hitherto the largest known species of the order Pythonomorpha, exceeding twofold in its measurements the JL. gigan- teus of Belgium. So the present saurian is much larger in dimensions than the New Jersey species I have called MZ. maximus. If, as appears certain, the Mosasauroid discovered by Webb measures seventy-five feet in length, and the AZ. maximus measured eighty, the M. dyspelor must have been the longest reptile known, and approaches very nearly the extreme of the mam- malan growth seen in the. whales, though, of course, without their ball. Such monsters may well excite our surprise, as well as our curiosity, in the inquiry as to their source of food-supply, and what the character of those contemporary animals preserved in the same geologic horizon. 4 i * Jr. 177 The locality whence this reptile was first procured is near Fort McRae, in New Mexico. It was discovered by Dr. W. B. Lyon, surgeon at that post, and by him sent to the Army Medical Museum, at Washington, whose director placed it in the collection of the Smithsonian Institution. The attention to the paleontology of his neighborhood by Dr. Lyon will always be cause of satisfaction to students, and his name will be remembered with that of Turner (discoverer of the H/asmosaurus platyurus, Cope), Sternberg, and others. Liopon NEpPa:oLIcUS, Cope. Rhamphosaurus nepeolicus, Cope, MS. Represented by the mandibular and parts of the maxillary and premax- illary bones, the quadrate, a dorsal vertebra, ete, of a single individual. These all indicate an animal related to the large ZL. proriger, but not more than one-third the size or less. It is about the same size as the L. micromus, Marsh, but is much more like the LZ. proriger in characters, so as to render it important to ascertain whether it be not a young individual of that species. An examination having convinced me that such is not the case, the points of distinction will be given farther on. The premazillary is very prominent, forming a rostrum, whose inferior face is narrowed, and suddenly descends to a prominent transverse ridge, which bounds the anterior alveoli in front.. The four premaxillary teeth stand on an area a little broader than long. Extremity broken. The anterior suture of the mazillary is vertical and zigzag. It displays a lateral contrac- tion just behind the first tooth; while the anterior margin of the nostril is above the third tooth. The teeth of both jaws have broadly oval bases, and apices with two cutting-edges and lenticular section. The inner face is more convex than the outer, most so in the anterior part of the jaws, and neither is faceted. The enamel is finely striate-grooved, especially toward the base. The mandible is light and thin, and diminishes in depth posteriorly. The coronoid is small, and the angle is produced backward and but little down- ward. The rami are not complete; the large portions preserved exhibit teeth at intervals of precisely an inch. Professor Mudge, who discovered the specimen, states that the jaw, when together, measured twenty-six inches in length, which would leave thirteen inches for the dentary bone. This is not far from the true number of teeth. The quadrate resembles that of L. dyspelor in various respects. The 23 C 178 internal longitudinal ridge is very prominent, and extends from the proximal angle to the distal articular face in line with the plane of the short acuminate hook. The great ala is narrow, and rather stout; the proximal articular face slopes steeply outward. The stapedial pit is a narrow, straight groove (per- haps partly closed by pressure). The knob is represented by a longitudinal crest, bordering the meatus below on the outer side, and not continuing to the distal articulation. The surface of the latter is crescentic, with an angle on the outer anterior border. This angle is the summit of a short, low, rugose ridge, which extends part way to the knob. Outer edge only of the great ala radiate-grooved ; posterior angle of distal condyle produced. The dorsal vertebra is somewhat flattened by pressure; but the ball was evidently transversely-cordate in outline. The bases of the diapophyses are very rugose; an angle from the articular cartilage is directed toward it from the rim of the cup. Inferior face with an obtuse median keel. The odontoid bone is deeper than long (fore and aft). . As compared with L. micromus, this species differs in the much less attenuated premaxillary and maxillary bones, the anterior nostril, and absence of facets on the crowns of the teeth; from ZL. proriger in the absence of narrow concave facets on the anterior teeth, and anterior position.of the nostril; from L. dyspelor in the less compressed, or less knife-shaped, dental crowns, and totally different form of the condyle of the quadrate. Measurements. ‘ M. Length of the bases of the two premaxillary teeth ---..----. -. 2. 2-2 - .20. penne teens wn rn n= cone 0. 026 Width of the bases of the two premaxillary teeth ------ ------ <= -- 5 222 one = eins en nee eee 0. 034 Length of the bases of the two maxillary teeth..--.. .----. ------ <2 22 25 = cone cone eons wo n= wn 0. 042 Depthof the anterior suture of the maxillary, -- = 5-2 anne = een em amin none eeleteete mete 0. 028 Depth of the maxillary at the end of the nares.-.. -.-...-..-..-.----.------2ee2-s--s---------- 0,038 IDE RO My WOE Oe) Sse ocesoo oes esco cae sees odes Sep econ sees ce So aosSessocasces cconadscs. (Oh(Wer ihenothvofitheldistalicondyle eos. eneae ene ware se ei oe ele eee als ete 0. 040 Wadthrofithedistal condyle -- 22 --)-2 4-1 cnc coon ee eee ee ee ee 0. 017 Width of the sreat-ala/on the inner side -.-. . 2... eo. ne 2 oe coma sone enewine wn en ae ones ianel= 0. 032 Width of the inner face above the meatus... -.. 2.58. oe ns oo nen wenn = wenn eeenine es eee 0.037 Henrthioftheyhoolfromithestapedial pit == -2.2 = =. 22 oe tame ee le 0. 028 Teng thiofiatdorsall V@xtC Dia eae mia tm mw faim alee om mn ol ee eA Diameteriofithe pall iverticall eee. -laaae saa elo cel ena oes mae ela ee 0. 029 Diameterof the ball transverse----\-+-- ---sie-- soe nee Sao ele = ee ae ee ee ee eee OAS This species was discovered by Prot. B. F. Mudge, who dug the type- specimen from the gray shale of: the Niobrara Cretaceous, half a mile south of the Solomon River, Kansas. 1856. 1857. 1858. 1868. 1870. 1871. 1872. 1873. 1874. 179 PISCES. LITERATURE OF THE SUBJECT. Leidy, Proceedings Academy Philadelphia, p. 73. Lepidotus: from Judith River. Leidy, 7 ¢., p. 256. Two species of Enchodus and Cladocyclus de- scribed. Leidy, Z.¢., p. 812. Mylognathus priscus, from the Fort Union epoch, described. Leidy, Z.¢., p. 167. Phasganodus dirus described. Marcou, North American Geology, p. 33. Ptychodus whippleyi de- scribed. Leidy, Proceedings Academy, Philadelphia, p. 207. Ptychodus occi- dentalis described. Leidy, @.¢., p. 12. Xiphactinus audax described. Cope, Proceedings American Philosophical Society, p. 529. Family of Saurodontide established and defined, and one new genus and four new species described. Cope, Hayden’s Report on Geological Survey of Wyoming, p. 424. Apsopeliz saurvformis described. Cope, Proceedings American Philosophical Society, p. 170. Genera Portheus and Anogmius described. Cope, Z.c., p. 827. Descriptions of twenty species rel nine genera ; characters of latter and of families Saurodontide and Strato- dontide extended. Cope, Proceedings Academy, Philadelphia, 280. risichthe nitida described. Leidy, Vertebrate Fauna of Western Territories, in Hayden’s Report of United States Geological Survey, vol. I, p. 288. Twelve known species redescribed and figured. Cope, Proceedings Academy Philadelphia, p. 337. Portheus lestrio and P. gladius described, and genus Daptinus defined. (April.) Cope, in Hayden’s Bulletin of United States Geological Survey of the Territories, p. 39. Synopsis of all the species; ten added ; genus Empo more fully defined. 180 1875. Cope, Proceedings Academy Philadelphia (January). Gar-fishes in Fort Union beds of Milk River. In the .present work, the families, genera, and species are more fully defined than has been heretofore practicable. ? PERCESOCKS. SYLLAZMUS, Cope. Allied to the Mugilide. A short spinous dorsal fin; ventral fins: abdom- inal, posterior to the spinous dorsal. Pectoral fins subinferior in position. Coracoid bones forming a compressed, keeled body. Scales large, cycloid ; lateral line present, extending along the middle of the sides. Parietal bones less than epiotics, entirely separated by the supradccipital. Frontal bones large, wide, their common suture distinct. The opercular apparatus extends obliquely backward, while the man- dible is produced forward. Hence, the inferior part of the hyomandibular and the symplectic are directed obliquely forward. The end of the muzzle is broken off, but the posterior part of the dentary bone does not exhibit any teeth. ‘The opercular bones are thin, and their inferior borders reach the median line of the inferior side of the head. The only species of this genus which has fallen under my observation is represented by a specimen in which the body posterior. to the femoral bones is wanting. The surface is covered with scales, so that only the out- lines of the femoral bones can be distinctly seen. These are thickened, and curved outward; those of opposite sides are well separated from each other. The scales exhibit.a very delicate concentric line-sculpture. The very posterior position of the ventral fins distinguishes this genus from Mugil, while the inferior position of the pectoral fins is not seen in Atherina. The lateral line does not occupy the inferior position seen in the Scombreso- cide. As compared with Apsopeliz, Cope, from the Benton group of Kansas, Sylemus differs in the absence of continuous dorsal radii or interneural spines anterior to the ventral fins. There is doubtless some affinity between the two genera, as the other characters are quite similar. I was unable to detect a lateral line in Apsopeliz. It is possible that a catalogue-name of Agassiz, viz, Calamopleurus (Poiss. Foss., V, p. 122), refers to this or some allied genus; but Tam unable to discover that it has ever been described. — 181 SYLLAMUS LATIFRONS, Cope. Represented by the entire head and body of a fish as far as the basis of the ventral fins, excepting the end of the muzzle. The scales are com- pletely preserved, while only the bases of the fins remain. The body is subcylindric, while the head is broad and flat above. The inferior side of the head is contracted; the coracoids forming a keel, and the lower borders of the dentary bones being in contact. The angular portion of the dentary is strongly grooved on its inferior surface, and the proximal or anterior parts of the operculum display a radiate sculpture. The top of the head is smooth, excepting a slight radiate sculpture of the parietals. The outline of the parietals is subround, and a little more extended than that of the supraéccipital, which is a short longitudinal oval. There are twenty-six or twenty-seven longitudinal rows of scales, or thirteen on each half; those of the abdomen not differing from those of the sides. The lateral line runs along the eighth below the dorsal fin, originating just above the base of the pectoral fin. There are nine rows of scales between the occiput and the first dorsal ray. I count the bases of fifteen dorsal radii, which are all fissured anteriorly, excepting the first, which is rudimental. The anterior rays are stouter than the posterior, and they embrace the pos- terior part of the ray in front of them by the basal fissure. The posterior rays are much narrowed, and embrace but little. The pectoral rays are nomerous. The physiognomy of this fish ig rendered peculiar by the depressed form of the snout, with the narrow under jaw. It is impossible to be sure whether the muzzle was elongate or not. Measurements. M. Length of the specimen to the base of the ventral fin..---.--.. --.. 0.22. 222. eee. ween ee eee 0. 205 Length of the specimen to the base of the dorsal .-...---.. -.-----. 2-2. ------ .ese-- eee ee=e-e 0. 090 Length of the specimen to tho base of the pectoral ..-...........---. .---+.-..----.------------ 0. 075 Length of the specimen to the edge of the operculum....-...-....--.-----.-----------.-----<-- 0. 071 Length of the specimen to the edge of the predperculum ......-..-----------..------+------+---- 0. 055 Length of the specimen to the condyle of the mesopterygoid -...-..---.----- ------ -------------- 0. 029 IEC ANT Cr WDC HOON 1) TINO OHO coco coence codes cubune da5sab esbo506 cocoDoas SecHay Saoces O5de 0. C17 Mirnmeterofthe front between tholorbitseeccaa seas leese a= sseioe eel sem ceisisie in eieisee oa einen ioni== 0. 020 Diameter of the body at the middle of the dorsal fin. -- . - 25-22. 225 «ee oe een one ees nnn 0. 045 Depthiortheibodyatithelmniddleofstlesdorsaletineysceeraye= sls eeiee site sso lle cialeelo s cteteleieie eee 0. 050 The specimen was found by Lieutenant Marshall, of the Wheeler United States Geographical Survey, ‘‘near the summit of Pike’s Peak,” Colorado. The specimen has the appearance of having been derived from the Cretaceous 182 or possibly Jurassic beds at the base of this granitic mountain, and its occur- rence where found was doubtless accidental. PELECORAPIS, Cope, gen. nov. This genus embraces fishes with strongly ctenoid scales and abdominal ventral fins. There is a spinous dorsal fin, apparently short, and not continued over the ventrals. The ribs and apophyses are slender, and the dorsal ver- tebree short and pitted. The pubic bones consist of two antero-posterior plates, in contact on the middle line. The anterior portion projects to a median angle, and there is an angular projection of the lateral border. From the angle formed by these borders, a long, cylindric rod projects forward beyond the plate; those of opposite sides slightly converging. The general relations of this form are to the families which combine the features of the orders of physoclystous and physostomous fishes, viz, Scom- bresocida, Atherinida, etc. he pelvis has considerable resemblance to that of those families, but especially to that of Hzocetus. From this it presents subordinate differences. PELECORAPIS VARIUS, Sp. nov. Represented by portions of perhaps two individuals, the larger of which includes a considerable part of the body, the head and tail being absent. On this specimen, it is evident that the scales diminish in size toward the posterior part of the body, where they are small; on the anterior region, there are two scales exposed, in an oblique series, in six millimeters; on the pos- terior region, three and one-half and four in the same. The concealed portions of the scale are sculptured with minute contiguous concentric grooves, without any radii. The exposed portion is thickened with-a cementum-like layer, which is marked with a few radiating lines of pores, which sometimes unite into irregular grooves. Teeth of the comb numerous and strong. Depth of body at pelvis, 0".074; length of pelvis, 0".040; of lamina, 0.022 ; of rod, 0".022; greatest width of pelvis, 0".023; width at basis of rods, 0".014; length of seventeen consecutive vertebrae, 0".105; diameter of a dorsal vertebra, 0.007. Discovered by Professor Mudge in a lead-colored clay, probably of the Benton epoch, twenty feet below the Jnoceramus hed, two miles west of Sibley, Kansas. wv 183 ISOSPONDYLI. SAURODONTID. This family embraces carnivorous fishes, many of them of large size and interesting structure, which have as yet only been discovered in the beds of the Cretaceous formation. They are of interest to the student of com- parative anatomy, and also to the paleontologist, as they appear to have been the predominant type of marine fishes during the Cretaceous period in the North American seas, and to have been abundant in those of Europe. The characters already assigned to the family are confirmed by the new species discovered, and many additional ones added, as follows: The cranial structure can be nearly made out, and the following points may be regarded as ascertained. The brain-case is not continued between the orbits, and the basis cram is double and with the muscular tube open. There are no exoccipital condyles, and that of the basioccipital is a conic cup. The homologies of some of the hones that constitute the cranial walls are difficult to determine. The basioccipital is longitudinally excavated below. The exoccipital is probably a small bone, which embraces the basi- occipital closely, so that it is dificult to say whether the bone that joins the opisthotic below is the former or latter. The opisthotic has considerable transverse extent, and an articular surface behind, probably for the posttem- poral. The supraoccipital is keeled or longitudinally crested above, and is preceded by, or continued into, a longitudinal median extension, which contin- ues as far as the frontal bones on the middle line, separating entirely the lateral elements. It is uncertain whether this be supraoccipital, or, by homology with the Siluroids, conjoimed parietal bones. If this homology be true, we can easily refer the elements which bound the exoccipitals above, and the supraoccipitals on either side, to the epiotics. They occupy the posi- tion of the epiotics in Sadmo, and are produced upward and backward into crests which have free margins, both on the upper and postero-interior mar- gins. ‘The appearance of these formerly led me te suspect the presence of a fontanelle, which I am now able to assert has no existence. The extent of these supposed epiotics anteriorly is limited by the approach of the more lateral elements to the middle line. These elements are wide, and, offering attach- ment to the opisthotic, hyomandibular, and postfrontal, must be regarded as pterotic. The postfrontal is a well-developed bone. The frontals terminate 184 posteriorly near the middle of the skull, and are well developed. They are bounded in front by the prefrontals and ethmoid. The prefrontals are stout bones, directed obliquely downward, and terminate in a large truncate articu- lar face for a facet of the palatine. The ethmoid is generally wide, and ter- minates in an apex. It presents a large facet downward and laterally for the anterior articular surface of the maxillary, opposing a corresponding facet of the vomer. Anterior and exterior to this point it exhibits a lateral excava- tion for the superior condyle of the premaxillary. AXIS — Fig. 8—Cranium of Portheus molossus, Cope, one-fourth natural size (linear); a, supraoccipital bone; b, exoccipital ; c, basioccipital ; d, parietal; e, pterotic; f, epiotic; g, postfrontal; h, frontal; i, prefrontal; k, ethmoid; 1, hyo-mandibular; m, metapterygoid; n, quadrate ; 0, ectopterygoid; p, pala- tine ; 7, sclerotic; +, suborbital; s, parasphenoid; ¢, premaxillary ; u, maxillary ; v, accessory maxillary ; w, dentary ; x, articulo-angular. The opercular bones are wanting. Viewing the cranium on the inferior aspect, the parasphenoid and vomer are seen to form a stout axis, the former running well posteriorly, and fissured behind for the muscular tube. Neither supports teeth in any known species. Just behind the line of the orbits, the parasphenoid gives off a lateral process, : 185 at the base of which are one or more foramina. The postfrontal shares with the pterotic the support of the hyomandibular. The prodtic is elongate, and sends a crest downward and forward to the basis of the above-mentioned process of the parasphenoid. Superiorly, it bounds, with the pterotic and sometimes (Portheus) opisthotic, a large foramen. The premazillary bones are short, and form but a small portion of the upper jaw. The maxillary is elongate and simple. The hyomandibular is rather narrow, and does not present an elongate support for the operculum. The symplectic is well developed, entering far into the inferior quadrate. The latter is a broad bone, large, in contact with the metapterygoid, which is itself a thin plate, nearly attaining the pterotic. In Portheus, the pterygoid is well developed as a broad plate extending to the inferior boundary of the orbits. The palatine @xhibits a marked peculiarity in the genera of this fam- ily. It is a shortish bone, soon uniting postero-inferiorly with the ectoptery- goid, but supporting as its supero-anterior extremity a body comparable to the head of a hammer. This madleolar body, as it may be called, is a short- ened cylinder, with one extremity articulated to the prefrontal and the other to the posterior superior of the maxillary facets. This gives the latter bone a firmness of support unusual among fishes. It also probably permits of some movement of the maxillary in a horizontal plane, which, though small, would have the effect of considerably expanding the gape of the mouth, thus enabling these fishes to swallow large bodies, in the manner of the Mosasauroids of the same sea and epoch. The ectopterygoid is a large bone, and extends down on the front of the inferior quadrate. Neither it nor the palatine supports teeth in any of the known genera. The sclerotica of the eye is ossified in Portheus and Ichthyodectes. ‘This ossification does not cover the eye, is not a complete circle, and is unseg- mented. Little can be said respecting the hyoid apparatus in this family. Some superior branchihyals, preserved in Portheus thaumas, are short flat rods. Two long flat bones, in place between the dentaries of a P. lestrio, appear to be the distal ceratohyals. They terminate in some crushed basihyals, and are covered with minute teeth en brosse on the inner faces and superior margins. No specimen exhibits the entire scapular arch, but several preserve the scapula with adjacent parts; two, a Portheus and probably an IJchthyodectes, 24 Cc 186 display most of the elements in place, and several others exhibit the artic- ulation of the pectoral fin. In the genera named, the clavicle is a wide bone antero-posteriorly, and is connected with the epiotic by a strong osseous bar, and probably with the apex of the parietal by another bar. ‘The posterior part of the arch between these connections is occupied by the stout scapula. Its posterior face is principally occupied by three convex articular facets. It sends a short laminar continuation downward behind the clavicle, and turns inward above, with a massive body at right angles to its long axis. This transverse portion is supported by the coracoid, which is a stout, flat rod, narrower than the clavicle, and is appressed to the inner face of the latter nearly to its distal end. Its posterior border is separated from the clavicle by a deep groove, but the anterior margins are continuous. Above, it incloses a large foramen with the exterior part of the scapula. It is not now possible to state whether there is any precoracoid (Parker; ‘‘ spangen- stuck,’ Gegenbaur); but the upper part of the bone here called coracoid occupies the position of the praecoracoid in some fishes, articulating with the superior instead of the inferior extremity of the scapula, as is usual. Except in the elevated position of the scapula, the entire arrangement approaches that of the Siluroids; but the inferior part of the scapular arch is not hori- zontal as in those fishes, but vertically compressed. The articular facets of the scapula are convex: the inferior and largest is oblique; the median and smallest is situated behind the axis of the others. Behind the superior two, on the transverse part of the scapula, are two round fossee, in line, adapted for the reception of the condyles of two basilar bones. The pectoral fin is composed of osseous rays, of which the first is much the largest, forming a powerful defensive weapon. As the fossils are found, a number of these rays usually lie in close apposition, edge to edge; but they are not codsified, and in life probably diverged in the usual manner, extend- ing the intervening membrane. Their component halves differ much in form, and are easily separated; and, as they often occur in this condition, inex- perienced persons may be led to regard them as entire spines. The femoral bones, or those supporting the ventral fins, are preserved in specimens of Ichthyodectes and Portheus. They resemble those of many physostomous fishes, but present a number of characteristic peculiarities. Their posterior portion is massive and is expanded on the outer side to sup- port the facets for the ventral rays. They are also expanded on the inner side, and strongly united, in the case of Portheus, by suture. The anterior part of these bones is thinner, and consists of two parts,—an inner rod, and an outer lamina at the base of the rod. The rods, or styles, are directed forward, par- 187 allel to each other; the lamina is turned outward and upward (see Plate XLV, fig. 7, and cut, fig. 9). In Ichthyodectes anaides, the outer portion of the lamina is extended backward as well as forward; in a species of Portheus (fig. 9), forward only. The face of attachment of the ventral fin is infero- lateral, and in antero-posterior lme with the anterior rod; it is therefore within the line of the external margin of the lateral ala of the femur. The face is expanded in a vertical direction, and is subround. Its manner of articulation with the spines of the ventral fin presents a close analogy with the corresponding articulation of the pectoral spines with the scapula, so far as regards the first rays. Thus, there are two plane articular facets,—the one superior, the other inferior. Between these is a prominent and narrow transverse tuberosity, which bears an articular facet directed partially back- ward. Behind this, instead of the fossee of the scapula, there is another tuberosity, which is directed posteriorly. Thus, there are four facets, of which the largest pair supports the diverging halves of, the base of the first ventral spine. The middle tuberosity is probably in contact with a portion of the second spine; and the posterior tuberosity with the base of the third. IT have alluded to the ventral rays as spines, and such are the first three. Whether there are additional spines is more than doubtful, as in Portheus, at least, there are no other articular surfaces than those described. A pair of ventral fins, found in relation with their femoral supports, by Professor Merrill, and sketched on the spot before removal from the rock, embraces only the three spines; the halves of the first being separated, as is often the case in isolated specimens. Whether additional soft rays existed is also improbable; but, if existing, they must have been very few, as the basis for their support, such as exists in Salmonide and other physostomous fishes, is absolutely wanting. It is therefore improbable that the internal basilar bone was similar to that in the above recent fishes; though from the analogy of the pectoral fins, one would expect to find ventral basilars. There are two small bones in the specimen described, which, according to the sketch, occupied the position of basilars; and such they probably are. Each is an irregular discoidal body, with one, a concave facet on one side. The osseous condition of the ventral rays is a remarkable character in fishes of the general physostomous affinities of the Sawrodontide. It isa point of resemblance to the physoclystous or spinous fishes, for which the structure of the superior walls of the skull in some measure prepares us. A third kind of spinous ray was originally described by me as pertaining to the Portheus thaumas, and had been previously referred by Professor Agassiz to the genus Ptychodus (vide Poissons Fossiles). This is composed 188 of closely-appressed osseous rays of different widths, each of which is com- posed of narrow, oblique segments. The sutures of these segments are of different character in almost every ray: being in the marginal ray en chevron ; in others, step-like; and, in others, dovetailed (see p. 200, and Plate XLIV, fig. 4). I suppose this compound spine to belong to one or other of the borders of the caudal fin. The vertebree in all the species certainly assignable to this group are, where known, deeply two-grooved on each side, besides the pits for the inser- tion of neurapophyses and pleurapophyses, except in the cervical region, where the lateral grooves are wanting. There are no diapophyses. The caudal vertebrae are rather numerous, but not so much so as in Amia, nor are they so much recurved as in that genus. Affinities of the Saurodontide.—More perfect specimens received since the description of the cranial structure on p. 183 was printed, render it almost certain that the median bone of the superior cranial walls is a supra-. occipital; that the parietals are produced upward into an angle (epiotie, p. 183) on each side; and that the epiotics (opisthotic, p. 183) ferm the postero- lateral angles of the skull. If this interpretation be true, there is no opis- thotic bone. It is quite possible to interpret the superior cranial structure of the Siluroids in the same way, while the arrangement is very different from that seen in Salmonide, Cyprinide, Characinide, and Esocide, where the opisthotic is present, and where the supraoccipital does not present any such anterior prolongation. The structure of the scapular arch, if we except the position of the scapula, has much in common with that of the Siluroids ; while the two basilars and double articulation of the pectoral: spine are striking points of resemblance to the same group. As characters of more typical Physostomi, we have the maxillary arcade of the mouth, the form and position of the ventral fins, and the apparent absence of dorsal spines. The form of the bones of the mouth, the presence of symplectic, subopercular, and postfrontal bones, the basioccipital muscular tube, and the unmodified anterior vertebra, distinguish the Saurodontide widely from the Nema- tognathi, and ally them to the Jsospondyli ; and with the latter I have for the present allowed them to remain. It must not be forgotten, however, that the long supraoccipital and osseous ventral rays are physoclystous charac- ters, and that the form and position of the femora are much nearer to those of Belone than to those of any physostomous fish known to me. The three persistent vertebrae of the caudal fin recall Sadmo, while the dorsals nearly resemble those of the Clupeide. The peculiar malleolus of the palatine bone is closely imitated by the Pomolobus pseudoharengus (alewife); but in that 189 pseudoharengus (alewife) ; but, in that species it articulates posteriorly with a process of the ethmoid, instead of the prefontal. In the bluefish (Pomatomus saltatrix) there is a nearer approach; here, the malleolus articulates with the prefontal and maxillary, but with the latter only by a squamosal joint. The same species betrays a resemblance to. this family in the insertion of the teeth by roots in alveoli, but the roots are much shorter in the living genus. They are also accompanied by a series of foramina on the inner side of the dentary, as in Saurocephalus. Six genera are enumerated below as belonging to this family, of which one, Erisichthe, Cope, is placed in it provisionally : Synopsis of genera. I. Jaws without foramina on the inner face below the alveolar margin : a. Teeth cylindric: Teeth of unequal lengths; some of them greatly devel ope deetetes sis heya k aye see yy eet Portheus. Mee chigotge qual @lemeitlis sarees eee ee eee Ichthyodectes. aa. Teeth compressed, knife-like : Teeth of unequal lengths; some of the anterior « oneat lad ewe lone dew angers iey ae nse Erisichthe. Meethvequalass=ere Peis eels Pa ee) es ae Daptinus. II. Dentary bones pierced by foramina below the alveolar border : Teeth with*subcylindic crowns 2.225.252 55-2). Saurodon. Teeth with short, compressed crowns...-----..- Saurocephalus. There are some other forms to be referred to this family, whose charac- ters are not yet fully determined. Thus, Hypsodon, Agass., from the European chalk, is related to the two genera first named above, but, as left by its author in the “ Potssons fossiles,” includes apparently two generic forms. The first figured and described has the mandibular teeth of equal length. In the second, they are unequal, as in Portheus, to which genus this specimen ought, perhaps, to be referred. Both are physostomous fishes, and not related to the Sphyrenide, where authors have generally placed them. Retaining the name Hypsodon for the genus with equal mandibular teeth, its relations to Ichthyodectes remain to be determined hy further study of the HZ. devesiensis. 190 The view of the superior walls of the cranium given by Professor Agassiz presents characters quite distinct from what I have observed in Portheus. A species of Ichthyodectes, from the chalk of Sussex, England, is figured, but not described, by Dixon in the Geology of Sussex. A number of forms, erroneously placed by Agassiz and Dixon in the genus Saurocephalus, have been referred by Leidy to a genus he calls Proto- sphyrana,' with two species, P. ferox and P. striata. The latter much resembles a Saurocephalus, having equal teeth; while the former probably includes several species, and probably genera. The teeth first referred to it resemble those of P. striata; while others resemble those of Portheus. An examination of the figures of the mandibles of some of these in Dixon’s work, shows that the large and small teeth occupy different areas, separated by grooves, in a manner quite distinct from anything seen in Portheus; but it can scarcely be regarded as typical of Profosphyrena, which name, moreover, has never been accompanied by the necessary description. Dr. Leidy applied the name Xiphactinus to a genus indicated by a spine in some degree like those regarded above as ventrals of Saurodontide. Whether it belongs to any of the genera above enumerated, or, if so, to which of them, is a question which can only be settled by future investigation. The history of the definition of this family may be found in the follow- ing references: Proceedings of the American Philosophical Society, 1870, p. 529; Hayden’s Survey of Wyoming, etc., 1871, p. 414; Proceedings of the American Philosophical Society, February, 1872. PORTHEUS, Cope. Proceedings of the American Philosophical Society, 1871, p. 173; 1. ¢., 1872, February. Teeth subcylindric, without serrate or cutting edges, occupying the pre- maxillary, maxillary, and dentary bones. Sizes irregular; the premaxillary, median maxillary, and anterior dentary teeth much enlarged. No foramina on inner face of jaws. Teeth on the premaxillary reduced in number. Oper- cular and preopercular bones very thin. Cranial bones not sculptured. The fishes of this genus were rapacious, and, so far as known, of large size. They constitute the most formidable type of physostomous fishes known. Five species are known to the writer from the Niobrara Cretaceous of Kansas. These are represented by numerous fragments of many individ- 1 Transactions cf the American Philosophical Society, 1855. 191 uals, which include large portions of the cranium, two almost entirely com- plete. Others embrace jaws, and one a large part of the vertebral column, with segmented caudal rays. In one, these rays were found with the cutting pectoral ray above described, while the simple flat ventral rays occur with several specimens. In none have any traces of symmetrical spinous rays been found, nor strong interneurals capable of supporting such. In none of the more perfect specimens with crania have the segmented rays been found; but the fossil of P. thaumas, where they occur, is represented by a vertebral column and its appendages, which do not differ appreciably from those of P. molossus. In the cranium of this genus, there is a well-marked supraorbital rim. Each opisthotic forms a prominent angle, directed posteriorly on each side of the exoccipital. The parasphenoid is a stout and narrow bone, deeply emar- ginate behind for the passage of the muscular canal. It has a transverse expansion in front of the base of the prodtic, which rests on a backward con- tinuation of the same. This expansion is pierced behind by two round fora- mina. The shaft is abruptly contracted in front of the expansion, and is tri- gonal in section. The prefrontal extends downward and forward, and carries inferior and anterior articular faces for the maxillary; the latter vertically transverse. The postero-inferior portion of the ethmoid bears on its posterior extremity a concave articular face, which opposes that of the vomer. The floor of the brain-case in front of the prodtics is supported by a vertical style, which is bifurcate above, and rests on the parasphenoid below. There are large thin supernumerary bones attached to the upper side of the distal half of the maxillary, as in various clupeoid genera. ‘There is a chain of thin suborbital bones. The crest of the vertex is compressed, and, in one, at least, of the species, greatly elevated and overlapped by a super- ficial thin bone, which forms a laminar extension of the crest in front of it. There is neither enamel nor sculpture on the cranium in any of the known species. Of the teeth in general, it may be added that their pulp-cavity is rather large at the base but rapidly diminishes in the crown. The mode of succes- sion is by direct displacement from below. The young crown rises into the pulp-cavity, and destroys the vitality of the crown while the root is absorbed 192 Numerous empty alveoli are to be found in all the jaws of this genus, in which examination will often detect the apex of the crown of the young tooth. All the bones of the palatine arch are present in this genus. The ectopterygoid is curved and concave on its lower border; the pterygoid is, on the other hand, thickened and concave on its upper border, where it is also strongly beveled outward, forming the inferior internal boundary of the orbit. The metapterygoid is a large, flat, and thin bone, joining the greater part of the superior border of the quadrate. It does not inclose a foramen with the other bones of the arch as is seen in Characinid fishes. These bones are all in place on a block, which also contains pectoral spines of Por- theus. On another block of the same specimen, the bones of the cheek are exhibited in connection with the quadrate. One is a greatly-expanded, thin bone, with the middle portion of its surface coarsely pitted. It is adjoined by a much smaller laminar bone of an irregular, semi-discoid form, with the middle of the convex side with three obtuse processes separated by fissures. The corresponding bone in P. molossus is figured in Plate XL, fig. 9. The interoperculum is a subparallelogrammic bone, with an open sigmoid artic- ular surface at one end. In P. molossus, there are two short articular faces on the other end. There is, therefore, no doubt, a suboperculum, though I have not identified it. The proximal part of the hyomandibular of another large specimen displays a continuous narrow articular surface for the pterotic. The posterior portion is a protuberant condyle; the middle part narrower and con- cave; the anterior part truncate, and presenting forward. Not far below the proximal end, on the posterior border, is a condyle for the operculum. It is sessile and Fig. 9.—Femoral bones and ventral fin of a ? Portheus: not very protuberant, and is a right-hand upper figure, from above; lower figure, from yertical oval in outline. ‘This the right side; left-hand figure, from below. bone closely resembles the cor- responding one of Ichthyodectes anaides. An incomplete skeleton of another Portheus includes pectoral arch and spines, branchial arches, etc. 'The arches are extended posteriorly, and the inner surfaces of the branchihyal bones are covered with minute teeth en brosse, and support a few tuberosities. The branchial fringe is preserved, consisting of long and slender processes. 193 The spine supported by the scapular arch in Portheus and Ichthyodectes, is adefensive weapon. Proximally, it presents a concave articular surface for the scapula, with a short hook-like projection bounding one end. A specimen in relation, but somewhat mutilated, exhibits a flat, discoidal basilar bone, which is probably applied to one of the scapular facets. Two rod-like basilars are visible, and two round condyles, projecting from the mass at the base of the fin-rays, fit into the scapular cotyli. The principal spine is flat and curved; the convex edge trenchant beyond the middle. The posterior edge is obtuse but narrow, and exhibits a slight groove on one side medially. Proximally, there is a shallow rabbet, whose floor is transversely rugose. Several layers ofthe tissue of the spine beyond the basal portion are deli- cately longitudinally striate. The distal half is broken away. Length of fragment, 1 foot; width, 1.5 inches; thickness at middle, 5 lines. The © largest pectoral spine of Portheus in my possession measures 2.75 inches in width." The vertebrae in this genus are rather short, but not so much so as in sharks. In P. thaumas, nearly eighty dorsalg and caudals were preserved ; those without lateral grooves, or cervicals (the term not appropriate), are not numerous. There are not more than three vertebrae entering the caudal fin; a fact which is dificult to determine, owing to the concealment of the terminal centra by bases of radii. There are seven hemapophyses in the, support, all flat except the first, which is like those anterior to it. The sec- ond is articulated freely to its centrum, and is wider than the others. Its condyle is characteristic, being double, and with a foramen between it and the produced extremity of the posterior margin of the bone. It is slightly - separated distally from the third, but the remainder are in close contact. The radii of the superior lobe of the caudal fin extend at least as far down as near the end of the third hemal spine from below. The structure of these parts in the P. molossus is as in the P. thaumas, so far as preserved. An outline-restoration of this genus is given on Plate LV. The species of this genus may he distinguished as follows:, a. Two premaxillary teeth: Maxillary arch thin, deep, with narrow anterior condyle; large maxillary teeth five; third mandibular tooth large, behind a CLOSS:BTOOVE Le ae terre ete nee aie A cies care oases ree melee = P. molossus. Maxillary large teeth three; third mandibular small; without cross- f AROS Ile) MONG OEE I S665 Goo Sco asooeeanDOUlogcsuS bnpand4edons P. thaumas. aa, Three to five premaxillary teeth: Maxillary arch stout, deep, with heavy anterior condyle; larger POCO AVG etree sensors eee se ln Sayer ore aaNet sae lees ee P. lestrio. Maxillary arch thick and shallow; larger teeth five pee seiaceertoatys P. mudgei. aoe. Premaxillary teeth unknown: : Maxillanyabone deeplyconcavessmalliss.. <- sasecie sein awicl- os = P. arcuatus. 1See Plate XLII, fig. 4. 194 PorTHEUS MoLossus, Cope. Proceedings of the American Philosophical Society for 1871, p. 173. Represented by four individuals: one from Fox Cafion, near Fort Wal- lace, with complete cranium, and many vertebree and radii; a second from another part of the same, with large part of cranium; and a third and fourth from Lower Butte Creek bluffs, both with fragments of cranium and other portions. In the first specimen, the jaws are perfect and dentition complete. The premazillary is vertically oval, convex externally, nearly flat within, and more than half underlaid by an anterior lamina of the maxillary. The anterior or median margin is regularly convex, and exhibits no surface or suture for union with the bone of the opposite side. Its posterior margin extends obliquely backward to beneath the superior articular condyle of the maxillary, and has a ragged edge, though the suture is squamosal. Its superior margin is deeply inflected in front of the condyle, and then convex and thickened. The anterior margin is thick and rugose with tubercular exostoses. There are but two teeth, which are very large, and directed obliquely forward; the first is two-thirds the diameter of the second. The mazillary is a large laminiform bone, with the upper margin consid- erably thickened proximally, but much thinned distally. It is abruptly con- tracted at the distal two-thirds its length, apparently for the attachment of a supernumerary bone. ‘The extremity is curved saber-shape upward, and has an acute toothless edge. The teeth are four small, five large, and eighteen small. These teeth, except the largest, have cylindric bases; the crowns (and bases of the latter) are slightly compressed or oval; they are straight ‘and regular, and lean backward. The middle one of the five is largest, being six times as long as the small ones, but little more than half as long as the large premaxillary or mandibular. The surface of the maxillary is rugose with small tubercles on its lower half, and has shallow grooves for nutritious vessels running downward and forward. The mandibular rami are short and deep, and have but little mutual attachment at the symphysis. ‘hey are not incurved at that point, and were bound by ligament only. There is no coronoid bone, and the articular is dis- tinct. It is short, of a rather irregular wedge-shape, and supports half the cotylus, above which it sends a short acuminate process. The angular has a prominent angle, like half an ellipse, somewhat contracted at the base; below 195 it is a rough, prominent, muscular insertion. The bone extends in a long sword-shaped process, on the inside of the ramus, to beyond its middle; externally, it is soon covered by the thin truncate edge of the dentary. This element is very large. rom the angular it rises steeply to a coronoid process, which has a slight outwardly-twisted eminence, and then follows a gently concave line to the symphysis. ‘The teeth are as follows: Two large—a transverse groove; three large; four very small; nine medium; and two very small—total, twenty. These teeth have straight cylindric-conic crowns, with cementum without striz or facets. The larger are a little compressed. Measurements of the jaws and tecth. M. Leneth of. the premaxillary bonejon the alveolar border. .-.--.-.-...---2 22.55 -c2n-- oo-- eee oe 0.045 Depth of the premaxillary bone on-the alveolar border -.-.-..----.------.----- --.--- e-0------- 0.093 pubic esssouguheralyeolarsmarciNeeast erence cease eae eaee eee ee eee ee eeeee 0. 016 enoLhyofmhe crowneo fav heisecon dyuOOt lee ereect ree spe ee eae satellite se siete esate etree ella l= 0. 046 Diameteriofitheicrownyof thejsamesatithe bases. .- 2) 22 1s ee eyae se eisiee 4) see seers sieiei-el= <= 0.014 Wencohorthemaxillarys bone: trom theipremaxillary, 2s se1s sees se ale eerie ine) -leeeie eect = ai 0. 270 Deptihtofsthemaxallaryaboneatibhe;condylemssesena saat sae eee ee sae eset mietee ae eeeeece 0. 080 IDE TAN GE The. aay Ay HORE Aly WN MCWVNO 6 Sooo seasass anes Goceans souecdeokas, sscene cnecosne 0. 046 ene thio thercrownyon themthindlarge soothes ssn. sss eee cise eee eeeieee eee deaeoeconerc 0. 028 Mrameteriofuhecrowmiabitheybaseaeencea=ne ees scesen eee alse seecissereeeecieercs cece cone 0. 011 Length of the crown at the second small tooth from the large...--..-..------------------+------ 0. 006 Minmetemotauuetcro wma LNe ase setae eee aiee ee chee ere ae aie eins cleats ceicisteeie seme 0. 004 Mens thKotmtheyramusemandibulig-se armen ese cee see ete sealer eee eee secieece 0, 350 IES VLTHN GETING BND On sccog sacked ssabou secu uadaHenbde Aaoe se. odcsen nb cGdbacod badacoecsnaS deseo 0. 040 Length of the angular bone exteriorly .----- BP Se VA eter S a Ue eerste Me mray ET I Nara Re ee niet iatetae S 0. 080 Depth atpuhercoronoideprocesseeciece ce eee ete aaeeetcie eee aeons sac al? Depth at the fourth tooth. ........-.. Se epee Soe See SaaS SSR ete mens Hsetoeseris ce sie 0. 080 encthvofthe:crownofithertirstitoothyesee se meeeeeacsece cae secee sane ose ceeeee eae eecis esate 0. 038 Diameter of the crown at the base.----. eee Mie prea ae eee gs Geta eee ech Ease ra one sis 0. 011 iene throtathexcrowniotathetourthwtoothpecees asses sees aaee ease ae aeeee eee eeeieeenee aes 0. 055 Drametertohthe;crownzatsuDeuWaSseree= ose a eseeet ree epee eee Cee eee ee eee 0, 016 The opercular bones are thin; the operculum broad; the predperculum rather narrow. ‘The latter is without armature, and has some shallow grooves radiating toward the circumference. Length of bone vertically, 0™.245; radius from inner curve, 07.09. The vertebre display deep lateral grooves; articular faces smooth. Length of centrum, 0".028; diameter, 0.043. The fan-shaped hzmal spine, or second of the caudal fin, is like that of P. thauwmas, but smaller. The last caudals contract in size very rapidly; the cup of the penultimate, or last, is transverse diamond-shaped. k The fragments of the saber-shaped vexisal spine display several layers of parallel striate dense bone; and the edge is tubercularly dentate, and one side ismuch more rugose than the other. At the base, one side is flat, the other convex; and there is a transversely rugose band near one edge. 196 The scales are thin and cycloid, and, though large, are not remarkably so for the size of the fish. They are not readily preserved. Measurements of the cranium. M. Length from the angle of the opisthotic to the anterior extremity of the ethmoid ..--.........-. One Length from the angle of the opisthotic to the front of the prodtic.-..-.-.--.--.----.---.-----. 0.11 Length from the postfrontal to the prefrontal across the orbit ...-.----..--.--+------+----.------ 0.11 Length from the occipital condyle to the transverse process of the parasphenoid.-.......-..---. 0.117 Length from the occipital condyle to the bottom of the parasphenoid emargination ...........-. 0. 055 Length of the parietal bone on the outer suture... ~~. 2. ---o-. ne cis cnn ee nice a ae 0. 07 Widthtofthesparietal boneatitheymiddless esses. — niet a= olen ael sein aeleee eae e eee eee 0.014 Width of the parietal bone to the edge of the pterotic...-....---. ..0.-. 2-22. - eee cece ee oo 0. 07 Width of the frontal at the middle of the orbit..--.-..---. ---. 05 n. 220. oo one eee n ne en ene ones 0.04 Widthrofthe parasphenoid at thejmiddle orbits ss=-- eae ele seine eee seoeeeee sees. 0.03 Ihen's thtofthennterioriquadrateyeecseere sce -leceeesieeeen cen eecioseciee ree sere acer encist cere eee 0.10 Length of the condyle of the inferior quadrate -- .----------.------ ..---. ------ ------ 22-22 0.03 beng thvofitheisymplecticeeerrnee me clee meee ee= emma eee SmobacesSSocsoSsEesdoncoKs GonD coc 0. 064 This cranium is figured on Plate xxxix. The gape of the mouth of the Portheus molossus extended the whole length of the cranium proper, and far beyond the orbits, since the maxillary reaches to opposite the occipital condyle. The orbits were large. The lower jaw was deep, and gave the countenance that bull-dog expression from which it derives its name. The body was stout and moderately elongate. A complete cranium of a Portheus, probably the P. molossus, for which I am indebted to my friend Professor Merrill, of Lincoln University, at Topeka, Kans., furnishes several points of interest previously unknown. The mouth is nearly vertical, somewhat as in Osmeroides, while the vertex is sur- mounted by an elevated crest. Hence, the superior and inferior facial out- lines meet at a right angle at the muzzle. The eye is small, and there is a suborbital chain of laminiform bones. The elevation of the skull is 16.75 inches, while the length is only 12.75 inches. Cut 8, page 184, represents this specimen. PoRTHEUS THAUMAS, Cope. Saurocephalus thaumas, Cope, Proceedings of the American Philosophical Society, 1870, November ; Hayden’s Survey of Wyoming, &c., 1871, p. 418. This large species rests on a specimen without cranium, originally pro- cured by Prof. B. F. Mudge. The parts preserved are not distinguishable from the corresponding ones in two individuals obtained by myself in West- ern Kansas, which include the greater portions of the jaws and suspensorial apparatus. These indicate larger animals than those of P. mo/ossus, and one of the most powerful of the physostomous fishes, rivaling in this respect many of the saurians, which were its contemporaries. Ol The distinguishing features of the species have been already pointed out. The premazillary is an obliquely oval or subpentagonal bone; the suture, with the maxillary, is not toothed, and the anterior or free edge is smooth, not tubercular, as in two specimens of P. molossus. There are but two teeth, of which the anterior is immense, and the second little more than half its diam- eter. The mazillary is stout, and supports in front four very small teeth ; then three very large, of which the median is largest. The teeth recom- mence very small and are closely placed in the same line; but, as the extremity of the maxillary is lost, the number cannot be stated. The dentary is similar in form to that of the P. molossus, but has rather more numerous teeth. Counting from the front, there are two large, one rather small; two large, and eighteen small and medium following; the smallest from third to ninth, inclusive. None of the crowns are preserved, but the alveoli are round, or nearly so. The large tooth of the premaxillary, if proportioned as in P. molossus, must have projected 0".0755, or three inches, above the alveolus; the fourth mandibular was but little smaller. Measurements of the jars. M. meno thvotstheypremaxall anyeesemeeieae celeste acetic ciel sais ee eerie cette siete araseleisieletelele eletelermisia= = 0.075 IDEN OF WG jOIeITERAITERAy coos cogeno dacs cosobe canoes ceQade donee saSeuE KduooR Bs oouEEC canse0 Des 0. 09 Depthrorstihe maxillaryeatithe condylesssas--msaa-)e ses eeee sae clss se ceisise cers sees sHHeso Gace 0. 08 Thickness of the maxillary just behind the condyle..-......----..----- sagooy doouce de 2 do4 eeeeue 0. 025 Mengthvor thedentaryeeseeeresee cece be cee eee ase cise ree seeeimneiiscinec tere een aie aaa 0. 25 Wepthroisthe:dentaryatiheisym phy sige eee eset eet toke eae ates ie alee iat aim ofa 0. 08 The various portions of cranial bones preserved are much like those of P. molossus, but stouter. The hyomandibular is nearly perfect; it is thin, but has a convex rib extending to its acuminate extremity at the postero-inferior angle of the metapterygoid and the superior extremity of the symplectic. The predperculum is attached by a thickened grooved margin, aid is not overlapped by the hyomandibular. It extends in a curved form round toward the condyle of the inferior quadrate. Three elongate bones, closely appressed, I suspect to be part of this bone, with the interoperculum and superior cera- tohyal adherent. The last is rather narrow, and with smooth distal articular surface, without suture. The superior branchihyals are a little like phalanges of Mosasaurus in form, being subsimilar and expanded at the ends, and much flattened. The parasphenoid is similar to that of P. molossus. The position of the hyomandibular is vertical to the axis of the basioccipital, the superior part directed forward. 198 Measurements. . M. Length of the basioccipital to the end of the muscular foramen -.-.-.---..----..-------+------- 0. 077 Gengthyofsthe hyomandibulateseece = ase ces ce aor eae aaa eee elem eee eee eee ere ee 0. 260 Lengthvofitheinferioriquadrate) (oblique) 22 -=-. 5. <2\----- 9 -see cee eee seiceieeic ees saree ieee 0.113 Length of the condyle of the inferior quadrate .-....-.----.-.--- 2-2. 2-20 2-9 eas wees = ene -e 0. 036 hens throftheipreoperculum preserved merc isc ca\- also melee ates ce ape eeise ies inte eee eet 0. 305 A portion of one of the flat unsegmented or ventral spines preserved exhibits an irregular rabbet on each edge of one side; width, 0".042. The sclerotic bones are as already described. A second specimen is still stouter in proportions, as the following meas- urements show: Measurements. M. Diameter of the maxillary condyle. .---..-.-..----.-----.------ = Seo aod HosocRecede sadubsneéseo 0. 034 Diameter of the maxilla above; behind the condyle.--..-..-.-. ..---. --..---- 22. s2-- 25-235 == 0. 033 Length of the angle of the jaw (exteriorly) -------..----. .--- -2-- 2-2-2 = 200 = een ee nnn e wna ne 0. 056 Diameter of the paraspbenoid at the middle of the prodtic ......---..----..----.--------------- 0.03 Diameter of the! dorsal vertebra (crushed). -----< 22. coon wow nne wow nn wee ee eens 0. 067 The diameter of the vertebra must be corrected by a little reduction. The largest fish-vertebree I obtained may be here mentioned. They are peculiar in having numerous concentric grooves on the articular faces, as in Ischyrhiza. ‘hey are otherwise as in this genus.. Length, 0".04; diameter, 0™.062. A peculiarity of dentition is observable in the two specimens first described, and in less degree in P. molossus. A considerable number of alveolae support no functional teeth (though included in our enumeration), but are occupied at some point by successional teeth. In some cases, the mouth of the alveolus appears to be narrowed by ossification, even where the tip of the young tooth is in sight; in one case, so far developed as to close up to the projecting apex. In other cases, the orifice is entirely stopped by the ossification, which presents the appearance of a scar with radiating lines of pores. The first specimen was discovered in a denuded area among the lower bluffs of Butte Creek. The flat cranial and jaw-bone occupied the summit of a cone of twenty or more feet in height, a relic of the ancient blue lime- stone strata spared from the surrounding denudation. The flat bones had shed off the water, which, running off on all sides, had formed the cone. The second specimen came from Fossil Spring Cafion, near the remains of Platecarpus curtirostris. r, 199 This species is also represented by wholes or parts of from seventy to eighty vertebrae, with numerous neural and hemal spines and fin-radii, and, perhaps, some ribs. There are no teeth nor cranial fragments. The bulk of the vertebre is double that of those of Daptinus phlebotomus. The vertebre present the usual two inferior, two lateral, and two supe- rior grooves—the last for the neural arch. There are no cervical vertebre; for these characters show them all to be dorsals and caudals. The suture for the neurapophyses forms a regular angulate convexity projecting downward. The arch is not closed above anteriorly, and is expanded laterally, while the spine is directed very obliquely backward. The concavities of the articular extremities are equal in the dorsals; but, in the caudals, one surface is much more deeply concave than the other, one being funnel-shaped, and the other nearly plane in a few. A number of consecutive vertebrae which represent the posterior portion of the caudal series are preserved One of these is fortunately the very extremity; and they demonstrate the tail to have been vertebrated or hetero- cereal, after the manner of Salmo. On the anterior three of the series, the lateral grooves have disappeared from the centra; the neural canal is very small, and the spines are very massive and curved backward, but much less so than in the more posterior parts of the column; they are flattened, wider than deep, and in close contact with each other, except the anterior of the three, which presents a narrowed edge forward. ‘The heemapophyses are thin, and suturally united to the centrum by a flat gomphosis. The terminal series embraces six vertebrae, which have a minute or obsolete neural canal, but bheemal canal distinct, but apparently interrupted. The hazemal arches are united to the centra by a rather smooth suture. The general direction of these vertebree forms a light upward curve. The heemal spines are flat and laminar, and their margins in contact; they decrease in width and length to the end of the series. The neural spine hes obliquely backward, and has a narrowed anterior ridge, but stout shaft. The anterior heemal spine in place exhibits a subglobular base, like an articulation, and its shaft is wider than those posterior to it. It is a subtri- angular flat bone, with neck and subglobular extremity, which applies very well to a concavity between the anterior pair of pleurapophyses, but does not in that position preserve contact with the anterior margin of the succeeding spine. One margin of the enigmatical bone is thin and divergent; the other 200 expanded laterally and straight. The latter gives off a transverse prominence, like half a globular knob, before reaching the extremity. Just within the latter are two large foramina, which are connected with the extremity by a groove on each side, which meet im a notch where the thin edge passes into the knob. Both sides of the neural and hzemal spines are concealed in this species and in the Ichthyodectes prognathus by numerous parallel osseous rods, which are somewhat angulate in section. They lie along the centra of the anterior series of caudal vertebrae, but are not to be found on vertebre of any other part of the column. Numerous loose and fragmentary rods of the same char- acter accompany the loose and attached caudal vertebrae, and all of them according to Professor Mudge, belong to the ‘posterior swimming organ” of this animal. There is also a collection of these rods from the anterior region of the body, which Professor Mudge thought occupied the position of an anterior limb. They do not, any of them, present a segmentation such as would be exhibited by the cartilaginous radii of caudal and pectoral fins, and their nature might have remained doubtful but for the explanation furnished by the anterior compound ray or spine of the posterior, probably caudal, fin. This ray, as in the case of the pectoral spine and first anal rays of some exist- ing siluroid and loricariid fishes, is composed of a number of parallel rods closely united. These are in their distal portions remarkably and beauti- fully segmented, of which a very simple form has been figured by Kner, as existing in the pectoral spine of the siluroid genus Pangasius. This seg- mentation becomes more obscure proximally, and finally disappears alto- gether, leaving the spine and rods homogeneous. This portion of them is quite identical with the rods found in the positions of fins already described, and I therefore regard these as fin-radii of the attenuated form presented by eartilaginous rays of most fishes, but ossified sufficiently to destroy the segmentation. They are thus in the condition of the anterior rays of the dorsal fin of some of the large Catostomide, or marginal caudal rays of some Characinide, where they are proximally homogeneous and bony, distally seg- mented and cartilaginous. The segmentation above alluded to presents the following characters The spine consists of four principal parallel rods, of which the external on each side thins, the one to an obtuse, the other to a thin edge. The more obtuse edge presents a groove on one side, which is occupied by a very slen- 201 \ der rod, and a shallow rabbet along the flat edge is occupied by a slender flat rod. Of the four principal rods, the two median are the most slender, and the flat marginal the widest. Of the two median, that next the latter is the wider. The stout marginal, or probably anterior, rod is segmented en chev- ron, the angle directed distally and lying near the free margin. The suture of the resulting segments is entirely straight, except, when returning, it approaches the margin, where it suddenly turns to the margin at right angles to it. The next rod is segmented without chevron obliquely backward and inward; where it leaves and reaches the margins, it is at right angles to them, and the margin projects obtusely at those points. Between the ends, the suture is very irregular and jagged, sending processes forward and backward. The segmen- tation of the next rod is similar, but’ more regularly serrate; distally, it becomes as irregular as in the last. The transverse marginal termini of the sutures are serrate in both. The inner and widest rod presents a still more regularly serrate oblique suture with the truncate extremities; but, owing to the width of the rod, the near approximation of the sutures continues for a longer distance. When broken, the suture appears steplike. Measurements. M. henethvof atsacmentiofithe:()icaudalis pine. = 2-1 -a-n\ele/)= cletaereeece alsielesiele = aleiel=t=is)=/eisins iiss) oe eee eee 0. 300 Length. of the tooth-line of the premaxillary.<2-- 2-2-2. 2-2. --0--- see eee eee eee 0, 058 Depth of the premaxillary (axial)).-------5- see S: ccs eSecncc es 2b ee ee 0,095 ‘See Proceedings of the American Philosophical Society (on the fishes of the Kansas Cretaceons), January, 1872. M. Depthrofsthemaxillarysatithesecondicondy les care n- eer ce ese tein ae ln see es «-\aeaie selene eee ee 0 095 Depth of theymaxillary atithe twentieth! tooth: 5... .- oss. eae. amene core oe eonecersasecs cesses 0. 065 Diameter of the base of the first premaxillary tooth..........-----...---..---£.---------. ----- 0.018 Diameter of the bases of five of the large maxillaries ........--..---.-.---.+------+----------- 0. 052 ILE HES AO? TINO.GEMEIAT CIWOWGlsooo ca Soboto SoukeoascuEp age sud cand dose dooeas GboGuS BHSEBS sdoSeze 0. 270 Mepis atibhesecondwlarcoytoot haere sateen etsbeeei emcees telecine eis sseieteie ee ee ee 0. 095 Depth at the last tooth ..-....-... Gaotod UBabrESon Oobeep oOUEnS Dat douognes ENeEEO SOEBnS easo aaeead 0.105 Diameteror, shebaseior themirstsl anges too uM em acrsemaalaleri scene sec ersiielselarelatataier sae) cleleiatel= ea 0. 013 Diametenor theybasevof the second large; coop hys sects ae sieraltele teins elel=le asia seins er == = tetel=to) etoile 0. 020 Length of the crown of the second large tooth...-....---..---------- eaHess actie cada Seb6c0 SSHE 0. 050 Length of the crown of the sixth tooth from behind -.-...-.....-.--- pac nieas ae Me 0. 025 If of the same proportions as the P. molossus, the vertical diameter of the head of this fish would be twenty-three inches. The type-specimen of P. lestrio was procured by Prof. B. F. Mudge, of Manhattan, Kans., during his survey of 1872, near the Solomon River. Professor Merrill’s specimen was obtained from the same region. PoRTHEUS MUDGEI, Cope. Represented by portions of the jaws, with vertebra, of a single individual, discovered by Prof: B. F. Mudge in Trego County, Kansas. The prominent character is seen in the possession of four subequal teeth in the premaxillary bone, which, therefore, presents a relatively long alveolar border for their accommodation. The bone is also more massive than in the other species, and is peculiarly thick on the free anterior edge. The maxillary bone presents a similar character, and shows this fish to have been the most robust species of the genus. The width gf the superior border of the maxillary is greater than in the others, although the vertical extent of the bone is considerably less (see the measurements under P. lestrio). There are five or six subequal large teeth behind an edentulous space on the maxillary bone, while those on the posterior part of it are small. The specimen is smaller than is usual in other species of the genus. Measurements. M. Wid thiofitheypremaxillaryabonesessrmeseeeeeeeeie te sets oa ciseeseereiemineeeinesciemnsetenameciseeees 0. 054 Elevation of the premaxillary bone above the first tooth ...-...--...---..----..--------------- 0. 060 Mhicknessjof thejpremaxillaryabonetabmuhenmid dle sec serteeeicioeleitee «(ssinieeeepaic sl anse ciel epee ce 0. 021 Depth of the maxillary atithe condyle--- ~~ -. -- ooo. ee nee ween ees re nieen = cee es nenne 0. 057 Depth of the maxillary at the fifth large tooth... - 2 o-oo. sce ese ice ween ce wns ewe ncieensleace 0. 040 eng thor thelbasesiorathetiveslarge woebheeree seer eery cesses cleccisecieraalseaeancios cies sein eae 0. 036 Beng thiofeanvan veri olverbe brane see aerate eincascieeee eee cieseae dee se ceieeeeeae seco séseq- ULM) DM iaAMEber, wv eLrticalrs = saps ae Te eae oe ete animale lays aed Sms ae Seiee nisms secieeese 0. 031 Diametersatransy ClsOyeoseeis ween ele ihe aces Sele Sear odes e ceatecoc/eselocelsn cise = eioeets 0. 031 Occasionally, the P. /estrio exhibits one, or even two, minute additional premaxillary teeth, but it exhibits but three large teeth in contradistinction to the four large ones of the P. mudgei. 204 PoRTHEUS ARCUATUS, Cope. The smallest species of the genus, equaling Ichthyodectes ctenodon in size, is represented by incomplete maxillary and palatine bones, and perhaps by accompanying vertebree and other pieces. Apart from its small size, this species may be known by the compressed and concave alveolar border behind and below the posterior maxillary condyle, and the very small size of the teeth which protrude from its subacute edge. The superior border behind this above-mentioned condyle is oblique, and its anterior border an acute edge. The interior face of the maxillary is convex; the exterior plane, and anteriorly dotted with radiating lines of pore-like impressions. This species is less nearly related to the preceding species of Portheus than they are to each other. Measurements. . M. Depth of the maxillary behind the second condyle 7... -. - 22028 .s-206 2nd oo ae dete cen ne ae cieiee oa 0. 025 Thickness of the maxillary behind the second condyle.-.---..-2.------..------ .-1--- ---2e2 +> 0, 004 Wadthiof the secondscondylecs- = Jase ae) cet coe ee ereme sae ene eee eee kere eee eee eee 0. 007 Length of the articular segment of the palatine:.--.. .----- 0-22. 2222-2 so-so. ene oe ese msceieees 0.010 From the yellow chalk of the Solomon River, Kansas. Found by Prof. B. F. Mudge. OBSERVATIONS ON TRE. PECTORAL AND VENTRAL SPINES OF THE GENUS PORTHEUS. As already stated, the fin-rays of this genus are readily separated into their constituent halves. The superior elements of the pectoral fin are laminiform and concave on the side in contact with the inferior halves, which they somewhat exceed in width. The infertor halves are massive, and exhibit a strong superior rabbet on the posterior margin for an overlapping — border of the second ray. On the anterior margin is a more shallow rabbet, which soon disappears, which is covered by the superior lamina. The posterior rabbet also disappears at a point varying with the species. The superior lamina bears the cotylus and adjacent hook, which embrace the superior scapular facet; the inferior half supports the facets which correspond to the inferior two of the scapula. The front of the pectoral spine is sharp-edged, forming a thin blade, hardened by a deposit of dense bone, which is transversely roughened. The blade is the edge of the supe- rior lamina, which extends beyond the equally acute border of the inferior half, the latter fitting closely to the concave inferior face of the former. Both faces of the spine are covered with a dense layer of bone, which is marked with delicate longitudinal grooves; and, when the superficial layers’ are broken away, the deeper ones are found to be grooved in the same manner. ‘This pectoral spine is a formidable weapon, measuring between two and three feet in length and two inches in width in a Portheus thawmas whose mandibular ramus is a foot in length. The ventral rays considerably resemble the pectoral, but are relatively weaker. The second and third are much smaller than the first, have a longitudinal rib on the side of one of the angles, and are scarcely flattened. The first is much flattened, and exhibits a sharp anterior edge, formed by the projecting border of the thinner half: The capitula of all the rays are strongly curved to a beak-like apex, bearing a tuberosity on the convexity in the two smaller ones. They differ from those of the anterior pectoral spines in the convexity of their articular facets, as they do not embrace the facets of the femur as do the pectorals those of the scapula. Like the latter, the dense superficial layer of bone is often finely striate-grooved. ICHTHYODECTES, Cope. Proceedings of the American Philosophical Society, 1870, November; Hayden’s Geological Survey of Wyoming, etc., 1871, p. 421. Teeth equal, subcylindric, in a single row, sunk in deep alveoli. Premaxillaries short. No foramina at the bases of the teeth on the inner alveolar walls. Vertebrae deeply grooved laterally. The species of this genus are, so far as known, smaller than those of the last, and, as their remains are more perishable than those, form less striking objects among the fossils of Kansas. They are, nevertheless, very abundant, especially in species, five of which are now described. The general structure in detail is much like that of Portheus. The maxillary bone is not contracted distally for a supernumerary bone, as in Portheus. The quadrate is similar, and the symplectic has a wide exposure on its outer face in L anaides. An entire anterior spine of the pectoral fin of I. anaides is preserved, the halves partially separated (see Plate XLV, fig. 8). The superior half is wider than the inferior. and projects beyond it, forming the trenchant anterior border, which is roughened’ by a deposit of dense osseous material. The inferior half is but little thicker, and has an acute posterior border; its surface is delicately striate-grooved. The spine widens distally, and thins out to an oblique, irregular edge, and was doubtless con- tinued as cartilage. A ventral spine accompanies the bones of J. prognathus and J. multidentatus, which is of a more robust form than the above-mentioned pectoral, but not so wide. The vertebree are deeply longitudinally grooved, as in Portheus, with the exception of a few of the anterior. 206 In a series of vertebree similar to those of this genus, those included in the basis of the caudal fin are not more than three in number. The species are distinguished as follows: Premaxillary teeth 5, second most prominent; maxillary not concave; dentary with 380 teeth, and biconvex alveolar border, with obtuse extremity...-...------- T. anaides. Premaxillaries?; maxillary straight, large, with 40 teeth; dentary straight, not produced at end; teeth 26---.-- I. ctenodon. Premaxillaries 5, first most prominent; maxillary concave, narrow; teeth small; dentary with a hook at apex, teeth Dire oe wits eet een eye ee eee I. hamatus. Premaxillaries 7, first most prominent, compressed; smaller. £ prognathus. Premaxillaries 12, second most prominent; the bone much narrowedsabove., smaller === eee =e eee eee 1. multidentatus. The English species of this genus is figured by Dixon in the Geology of Sussex, Pl. xxxii, Figs. 9 and 9*. I can find no letter-press nor name relating to it, and cannot determine its specific characters from the fragment- ary character of the piece of mandible figured. . IcHTHYODECTES ANAIDES, Cope. Indicated by two individuals: one with both dentary bones and teeth, with vertebre ; the other with many portions of cranium, fin-rays, vertebree, and other elements more or less separated. The latter were all taken from the upper face of a spur of a limestone-bluff, elevated about five feet from the ground-level, where they were denuded and exposed as on a table. It is the largest species of the genus, and the anterior premaxillary teeth are larger than-the posterior. The premazxillary bones are oblique ovoids, very convex on the external face, thinning laterally and above. The superior mar- gin presents a thickening bearing an articular surface, while behind it is an open gutter-like inflection. The large teeth are quite cylindrical. Both these bones are preserved. But part of the right maxillary remains. It is thickened above in front of the condyle, and is regularly convex at that point. The teeth are small, there being 10.5 in an inch. The margin is not concave. The mandibular rami are preserved almost entire. They are short and deep, and have a short angular process, which is relatively shorter than in 207 Portheus. The margin rises steeply to the dentary, which presents a nar- rowed rectangle behind. The alveolar margin has two convexities, with a depression between; the symphyseal angle is not prominent. The lower posterior angle of the dentary is quite prominent for muscular insertion. The crowns of the teeth are cylindric, slightly curved inward. The dentary bones of the second specimen coincide with these in all respects. Thirty-three vertebre are preserved, all deeply two-grooved on the sides. The ribs are articulated by a sigmoid surface to a broad, short element of a sigmoid form, which is inserted in the lateral groove of the inferior face, or articulated by gomphosis. The ventral spines already noticed are quite flat, without serrate edge, but with some rugosities near the edge on one side only. ‘There are no grooves on the upper side, but the dense bone is delicately striate. Measurements. M. IEG GHAN OE UNS PROTEIN RY 6oe5c0 eSocce cose coneed esosno sESoes esseb05006 So00 dese Sae5 DEc0 9DaECS 0. 033 Depthiof they promaxillanye.- see asceiesee =e SdSco016eHd dad6c0 S660 NOSE Gadd BeeaSosa neGasene 0. 045 Depth of the maxillary at the condyle. .----- ---- -- 2-3. 02-2. enn oe owen cee eee e een oon e 0. 037 Thickness of the maxillary just behind the condyle ....-..----...--.. -----..----- socase soshas 0. 012 Length of the mandibular ramus...--...---. 2.2222 ss-=-------- J5G 008 H0sCdeS FeaceR aqedco poDaa6 0.172 ILCH RAN. OL ANS Arab Le MYOTIS od cde eonoindd ans ObroaS DoCoe See aBbalcdogds Hanes Aub ne coe cone Bodoce 0.014 Mepthyat ch eycoronoidaprocessee sss ssa = shesers ass ere se a elaial se estate lover eens oe meee ieeueecer 0. 058 Depthfatithessymphysissesse sss ses snes eo aa as se ecis ioemeteccisee, eee enten oe searisceceleseemcccse 0. 041 Henathoherchtivente) rower seems ees aes ae elstete seers eset nein ele ae maint ea leisterrate enlaces 0. 212 Wiidth\ ofstheranticnlanittaces. = s=iseccistcelcece cnc eels seiciew esac Hisecie ence isi ooee se seniciee seams eeee 0.03 Wi thro tsribgessesmmacer ere eer evaa cae ies Scie shee aie seu aie ete Siete opelse ste sees ate eels cic ous erator eee 0. 004 Widthrofethesventrolispineyatithermidel eye=ee- eae -seersecicea ns soeia weseiseeeciee eeeeseeerae ae 0. 025 Hensthiofathenventraluspine) (iracment)meeeaeeeenmaseieneecieecieneecen tise selec cise eee soos OL i1G enero fshercondyleoftherinterior quadrate) s-ssee ee sees ee cine ae es cieeaeiieeec eres 0. 020 The scales associated with this species were thin and cycloid, and diffi- cult to preserve. From near the Smoky Hill River, Kansas. IcHTHYODECTES CTENODON, Cope. Proceedings of the American Philosophical Society, 1870, November; Hayden’s Geological Survey of Wy- oming, &c., 1871, p. 421, part. Found by Professor Mudge on the North Fork of the Smoky Hill River; common in many other localities. This species is established on one complete maxillary bone, and three- fourths of the other, a large part of the dentary bone, with the entire dental series, and numerous portions of cranial bones. These, according to Profes- sor Mudge, were found together, and, to all appearance, belong to the same animal. 208 The dental characters differ from those of Saurocephalus, as above pointed out, and resemble more those of Sawrodon leanus. The crowns of the teeth are more exserted and slender. The inner face of the crown is more convex than the outer; but there is no angle separating the two aspects. The apex is moderately acute, and directed a little inward, owing to a slight convexity of the external face. Enamel smooth. The alveoli are very close together, and are probably only separated in their deeper portions. There are forty-two teeth and alveoli in the maxillary bone. The superior condyle is low, and its anterior border falls opposite to the last tooth, or the indented surface which was occupied by the premaxillary bone. The more proximal part of the maxillary curves inward and backward behind the position of the premaxillary, more than in S. prognathus. ‘Tne maxillary is a rather thin and narrow bone, with a broad obtuse and thinned extremity. Its superior mar- gin is marked with one or more acute ridges, which look as though it had a contact with a large predrbital bone. The alveolar border is nearly straight. The dentary bone is remarkable for its straightness and laminar charac- ter, and for the depth of the symphysis. The length of the latter is preserved, while posteriorly to it the lower margin of the dentary is broken away. The alveolar margin is slightly concave, and unites with the symphyseal at.an angle of 65°. There are twenty-six teeth and alveole, which grow a little larger to the posterior extremity of the series; anteriorly, the alveoli are confluent externally, but, posteriorly, the septa are frequently complete, though thin. In neither this bone nor the maxillary are to be found the foramina along the bases of the teeth, characteristic of Sawrocephalus or Saurodon, as pointed out by Harlan and Hays. Measurements. M. Length of the:marxillary bone .-;. --<-<-s52..--2 esc ones aces cone pase eee eeee ses eee eee 0. 158 Depth at the condyle .........----. BEES ee SCS non Onna eocc Son ecoasccsemeea sco ecce 0, 031 Depthvatithe: extremity.---)..-- 2-522. 0 s<. saccicccw cece sae eo enaeee Done oe ee ne ee eee em O ROS henethvof the crown ofa itooth)..-2..-. ~~... scccen csoacaccense See Ran oon eR GT Diameter’of the:crown atithe’base=.- 2... 222. c2 2. os. code ode en Seen ee ee UBS Leng thiofithejalveolar bordenof the dentary---..2-.-2s1-2+5 sas c)es ee eee nlee en ee eee e ee enn LO Depthiofithesymphyseal border ofthe dentary,-..---- +---- see ase eee eee 0. 047 LenethofitheoperaulariconGylolc--scs-s-se>-s 2+ --+ 2-22 ee as = oe ee Sacasscecr 0.018 Several osseous ventral rays accompany the cranial bones; they are prob- ably interior in position, and are much more slender than the ventral spines observed in L. anaides and I. prognathus. They are subquadrate in section, not sculptured nor enameled; there is‘a shallow groove on the side. 209 IcnTHyYOpDECTES uAMATUS, Cope. Represented by a considerable number of remains of an individual from the blue Cretaceous shale, near Russell Spring, on the Smoky Hill River. The characters which distinguish this species froin /. anaides are numer- ous; but they are less marked when compared with those of I. ctenodon, partly because the premaxillary bones of the latter have not been preserved. In the first place, the dentary bones of the two are of equal length, and support the same number of teeth, while the maxillary of / hamatus is shorter, and supports more teeth; it is concave at the proximal part of the tooth-line, but is straight in the corresponding part of £ ctenodon. ‘The end of the dentary is furnished with a strong obtuse process or hook directed upward and for- ward, not seen in I. ctenodon. The maxillary behind the premaxiilary is in this species thickened, and with two articular surfaces; the proximal looking outward, the distal inward, and separated by an oblique ridge from the con- dyle. In £. ctenodon, there is but one smooth surface, gradually narrowing with the thinning of the bone from the condyle. The premazillary is less extended antero-superiorly than in the species already described, but supports, as in it, an articular face. There is no grooye behind it, as in J. anaides and Portheus. Wt displays a surface for osseous articulation to near its extremity on the inner side; while below it, and on the external faee, near the basis of the first and second teeth, the surface is rugose. Maxillary teeth, forty-three. The dentary supports twenty-five. The anterior hook is obtuse, and rises abruptly to above the apices of the crowns of the teeth. It is knobbed above, and supports a tooth not larger than the others. All the cranial bones preserved are not sculptured. Portions of the thin flat ventral spines display the delicately-grooved striation already observed, while the trenchant edge is bordered-on one side by raised /ongitudind striz. ‘The other side is minutely pitted. The vertebre are anterior, and without lateral grooves. Three ef them are 0.06 in length; an undistorted one is a little wider than deep, and the cup is 0".026 across. Measurements. M. lip Grito nae AMEND ON, Gono cascode ecco cope aden oe une anon GeSl cone odes HeAO nena AadeBen a: Ub IZE! Depth at the symphysis-- .--.---- Bp OS Bete dos Baeo COE ERE COD TES nO SEER SEE e CORO S Baap cern a sorons 0.055 Wepthrofihe premaxillarya (Oblique) ieesssesescoesen aan eee cieteate ce ee see esas see ee eee 0. 043 Length of the premaxillary (oblique) ...--... Séoa Chbonod sobURH sobH05 conS BadaeS sob bD Goog HHEaES 0. 026 27 ¢ M. Depth of the maxillary at the condyle.-.--------------- .-- 22-2 +--+ see 222 eee eens eee ), 027 Depth of the maxillary behind the condyle .----..---------------++ +++ +++ 222222 eee eee ee 2-2 eee 0. 023 Depth ofsthermaxillaryegneanithe mid dlessecn cel -rlelsesiel meine aaa ele ee eee eee ieee ere ereeee 0. 027 Wadthiofathesventralis pie mrstess me resielaielate ae oe elas ee ara aa (ole ae eae ee tate aerate eee are 0. 031 This species and the two preceding were not very unlike in size; the two following are smaller. IcHTHYODECTES PROGNATHUS, Cope. Proceedings of the American Philosophical Society, 1870, November (Saurocephalus) ; Hayden’s Geologi- cal Survey of Wyoming, &c., 1871, p. 417. In this species, the premaxillary is more rhomboid in outline than in the others, and is less convex externally. Of its more numerous teeth, the first is not larger than the last, differing thus from all others of the genus; it is in line with the nearly straight anterior margin of the bone, and is more com- pressed than in the other species. The surface of the bone is peculiar in a minute sculpture of impressed lines, or lines of puncte. There is a very small articular surface on the superior extremity. This species is represented by a premaxillary and attached proximal portion of the maxillary bones of the right side, and by a large number of ver- tebree and other bones. These portions were associated in the collections placed in my hands by Professor Mudge, and relate to each other in size, as do those of the preceding species and the Ichthyodectes ctenodon. The premaxillary is characterized by its great depth as compared with its length, and by the shortness of its union with the maxillary. The pala- tine condyle of the maxillary reaches a point above the middle of the alveolar margin of the premaxillary. ‘The latter contains alveole of seven teeth, the anterior of which only presents a perfect crown. It is elongate, compressed, equilateral, smooth, and acute. Its direction is even more obliquely forward than the anterior outline of the bone, which tself makes an angle of 50° with the alveolar border. The vertebrae consist of cervicals, dorsals, and caudals, to the number of about sixty, most of which are supposed to have been derived from the same animal. The grooves are as in D. phlebotomus; there being two below, two on each side, and two above. The latter receives the bases of the neu- rapophyses, which are in many cases preserved. The inferior pair of grooves becomes more widely separated as we approach the cervical series, leaving an inferior plane, which is longitudinally striate-grooved. This plane widens 211 till the grooves bounding it disappear. The inferior lateral groove becomes widened into a pit, which some of the specimens show to have been occupied by a pluglike parapophysis, as in Edops, ete., or a rib-head of similar form. The neurapophysial articular grooves become pits anteriorly, and these only of all the grooves, remain on the anterior two vertebre in the collection. Some of the posterior caudals preserve large portions of the neural arches and spines. ‘They form an oblique zigzag suture with the bodies, consisting of two right angles on each, one projecting upward anteriorly, another down- ward behind. The neural spines are very wide and massive, and in close contact antero-posteriorly ; these probably support the caudal fin. They are deeply and elegantly grooved from the basis upward. The centra exhibit no lateral grooves. | An unsymmetrical ventral fin-ray accompanied these remains, and, from its mineralization, color, size, and sculpture, probably belongs with them. The anterior margin is thinned, and with obtuse denticulations; the posterior trun- -cate. The section is lenticular, with a deep rabbet on one side of the posterior edge; section at the base circular, apex lost. The sculpture consists of fine, longitudinal, raised striee, which bifurcate and send numerous similar ridges to the teeth of the anterior margin. This ray differs from the corresponding one of /. anaides in its greater relative thickness, its anterior rugosity, and peculiar sculpture. Measurements. i M. Ihone GininGice GH UNOA DMO 545 ansccosbeccoonUbescosees conadobsuSeoe nepuoy DeeboUdoonoN beadcoer 0, 0245 ice GeaMNGee OF TAG GOING), scacad soGHes Gooads yasaas déoads ca6eds gUOKee gaaouaS eHduns Sade B500 0. 019 Meno thro fr WwOrceLnvicals|(MOLCISbOLted)Iamerceriacinrccstac selasmimcetesaetseeinsniies(anissisiesees teat 0. 033 IDE RNC OLE TINS IMB? C5S5 so55u0 BES RON BEB BTEOOnHSanbes BBonos GOnoos BSaooo saSecclannosEesusss 0. 021 Tsenothvotiayd onsale seers es cect an meee ante aiaanetemee saelake se ale ea steeinie suSboondbaoRGaed 0, 016 ength ofa caudal sesso asia iersis oes sees ee ee ea ee soe mee ae eon eeiseee aaseeee. sosenuecsee 0. 014 Width of the neural spine of the\caudal at the base. 2. 22. - 5220522 -25-2- 222 esse eens eee eee 0. 012 Length of the alveolar margin of the premaxillary:.-.-.-.--.-..-2-..-5.--2-s5----5---------- 01022 Length of the anterior margin of the premaxillary .-.-....---..----.----2---20---+--- e222 +--+ 0. 020 Depth from: the) condylevof themmaxillanyscea-- se -ceoee seas seeee eee seseeiae ed Set ears 0. 026 eng throt-theycrowmn-of the: premaxillanyatootliqness jjeisesse sa) seieinial- eeleeioe i siele= (Se sm iwe)ain esol == 0. 0042 Diameteriof thercrowilof the premeaxillary, tootheseeescaac-teciees cs sees eisecineese sees cecee ens 02002 A fragment of a large flat bone exhibits very delicate radiating grooves, which are marked by spaced impressed dots. From the North Fork of the Smoky River, Kansas, six miles south of the town of Sheridan. Prof. B. F. Mudge. This species was about two-thirds the size of the species last described. 212 ICHTHYODECTES MULTIDENTATUS, Cope. This species was first described from a premaxillary and part of a max- illary bone, from the Smoky Hill River; a second and more perfectly-pre- served skeleton, obtained by Prof. Merrill from the headwaters of the Solomon River, adds much to our knowledge of it. The first-mentioned specimen was described as follows : “Tn this fish, we have the convex premazillary of the larger species, with more numerous (twelve) teeth than in any other of the genus. Those of largest size are the first three, the last being small. The second and third are about equally prominent, and more so than the first. The bone is much contracted above; there beimg an excavation on the anterior border, and con- traction from behind. The superior edge is thin, and without trace of artic- ular surface. Alveolar edge somewhat rugose. The mazillary is both narrow and thin, but is only partially preserved. It bears five teeth on O™.01. One of these, with complete crown, displays a longitudinal angle on the antero-interior, face. Length ofthe premaxillary, 0".039; depth of the premaxillary (oblique), 0".023; length of its tooth-line, 0.025.” The second specimen is represented by a cranium with maxillary bone and scapular arch, vertebrae and ventral spines, ete. The specific characters are well exhibited in the dentition. There are thirty teeth and eighteen empty alveoli in the maxillary bone; and the anterior apex of the same, which is broken off; probably supported four additional ones.. The crowns have a subround section, and differ from those of other species in being marked with shallow sulci and longitudimal angles and ridges.. The most prominent ridges are, one on the middle of the external face, ‘and one on the outer side of the anterior face, but there may be two or three on the outer face and on a few posterior teeth; the outer face is smooth. The fragment with tooth, above described as typical, belongs to the distal part of the jaw. There are shallow grooves at the bases of the crowns of most of the teeth. The cranium has an elevated crest, which stands on the narrow median bone which I suppose to be supraoccipital. On each side, and just behind the crest, the parietal bone rises as a posteriorly-directed process. The epiotic also forms: a strong latero-posterior angle. ‘he pterotic extends roof- like on each side; its anterior part abruptly depressed below the posterior. The postfrontal forms a short transverse process, which is preceded by a con- cave excavation of its free border. The vertical position of the malleolar process of the prefrontal shows that this species possessed the subvertical mouth already ascribed to the Portheus molossus. The scapula is much like that of Portheus, and in the specimen stands ona level with the orbit. The ventral spine is of relatively large propor- tions, and its superficial dense layer is marked with rows ‘of delicate, i im- pressed puncte, which are sometimes confluent into grooves. The first cervical vertebra is. unmodified and grooveless; the dorsal vertebra are grooved. Length of cranium, 0".154; diameter of first vertebra, 0".020; depth of maxillary at middle, 0".023; width of ventral spine, 07.020; length of articular face of scapula, 0".031; width of clavicle below scapula, 0".040. DAPTINUS, Cope. This genus was proposed for Saurocephalus phlebotomus, Cope. Vhe form of the crowns of the teeth is that of Szurocephalus and Erisichthe; Wut it differs from the latter in their perfect equality of size. It differs from the former in the position of the nutritious foramina of the inner side of the dentary bone; for, instead of forming an isolated series, as in that genus, they only appear as notches on the inner margins of the alveoli. The mode of articulation of the premaxilary and maxillary bones with each other and with the prefrontals is similar to that already described in the genus Portheus. ‘The maxillary underlaps the premaxillary on its inner face, forming a very extensive squamosal suture, and presents the two superior condyles, the anterior for the ethmoid, the posterior for the palatine bones. The palatine presents the malleolar segment which connects the maxillary and prefrontal articular faces, and then continues downward and backward, as a vertical lamina, without teeth on its free margin. Immediately in front of each of these bones is a triangular element, compressed, with an acute apex upward and truncate base downward, the posterior border in contact with the anterior edge of the palatine. The vomer is toothless. The anterior vertebrze present pits for the neurapophyses, but no others, as far as the third. On the fourth and subsequent centra, there is a deep lateral pit, and a smaller one above and behind it, near, and a little posterior to the neurapophysial pit. The teeth in Daptinus are not a little like those of the existing genus Pomatomus, which includes the bluefish. DapTiINUS PHLEBOTOMUS, Cope. Represented by all the tooth-bearing elements of three individuals, from distinct localities, with portions of crania and vertebrae. ‘These show that the jaws are long and slender, and that the teeth are closely set, and with the roots but little compressed, while the crowns are very much so. Eight alveolee may be counted in fourteen millimeters. The dentary bones have a vertical and transverse truncation at the symphysis, and are thickened so as to afford strong attachment for something; the absence of the usual obliquity in the one or the other direction is noteworthy. The teeth continue to the symphysis, but of slightly reduced size. The internal groove of the dentary 214 is deep, and continued to near the symphysis. The cotylus of the articular bone is presented largely backward. The premaxillary is a large oval plate, gently convex on the outer side, and of greater vertical than transverse extent. It differs from that of Portheus in lacking the condyle on the superior border. In the best-preserved speci- men, a large piece is broken from its posterior alveolar border; in that which remains, nine alveoli remain. In two of the specimens, the anterior part of the cranium is preserved. The anterior part of the ethmoid is broad and convex above, and rapidly contracts to an acute, flat apex. Laterally, it overhangs the fossa in which the anterior maxillary condyle enters, and furnishes a flat surface for the posterior condyle of the same bone. The vomer is excavated laterally in front, so as to be somewhat cross-shaped, the apex being rather produced. It is edentulous. Measurements. M. Now depthiofithospremas i llany esses eens eee ee eee eee eee seme ete ea 0, 054 No: 1) depthyofthoimasxaillarysatithommiddlecsss 22s a sere eee neeee eee eee e eee ereee 0. 025 No. 1, depth of the triangular bone of the palate .----.-----.------.- So EaaeAUUnandsseSsaousbs 0, 038 Nos depthiofitheisymphysisiofith om andi Dniester eee 0. 026 Non2plengthofthrocvanterior-VervevLliencsee=> ssoene coe ae teee es aeeee eee Seno e eee eee 0. 040 Nose, diamoteriof ono anterion VeriObrac-s]= esse neee co onsen ae hee eee eee ee 0. 016 No. 2, depth of the dentary..-.-..-..--- SBS a Se SEED Cae ECDC SE AEE ERoIeeaon eciesad coha onod 0. 041 No:'2; ‘depta:of.tho/symphysis!:-c2->--2 = -.e soo tocee asec eo ee eee tie eee ee Eee eee 0. 026 No.2, width of the cthmoid' abovocs-c-- ssc coc. = s= = ase seein we reo cnien ae ac noc eee ee EEEee 0.0155 No.'2, width of tho) craninm atithe prefrontal facots.----.---. ------ «2 =--s-=seeelene eee 0. 022 No.2) lenwth of tho muzzleito thojprofrontallfaccts--- «=--sesen -aeees Seeee eeeeeee eee eee 0. 023 A third specimen consists of some vertebree and portions of the cranium; the latter including the dentary, maxillary, part of the premaxillary, the palatine and vomerine bones, compressed into a mass by pressure, the separate pieces preserving nearly their normal relations. From the latter, the following characters may he derived: Palatine bones toothless; teeth of both maxillary and dentary with compressed crowns, which are longer than wide at base, and closely placed; those of the dentary twice as large as those of the maxillary. Maxillary bone proximally deep; dentary shallower; the maxillary with elongate suture with the premaxillary behind. The teeth are equilateral, without intermarginal groove or barb, and with smooth enamel-surface, or only minutely striate under the microscope. A series of larger foramina extends along the alveolar margin of the maxil 215 lary and dentary bones, one foramen to each tooth. The alveole are confluent as they appreach this margin. There are three vertebr, which present two pairs of deep longitudina grooves, viz, two on each side, two on the inferior, and two on the superior face of the bone; the last receives the basal articulation of the hamapophyses. The centra are crushed. Their measurements, with those of the jaws, are as follows: Measurements. M. IER Oh Ce WING CONAN G6 okeond soocds ppooos Goes cnbboe Seceop 6GEs GOA ARS ES OBOGEE DAO Saas Soares 0. 025 Mongadinmeteni (crushed) eeemeeerate eset eee iat soo dooans sbepeesaae coco oHeseapeEs sacooeoada 0. 035 Shortidiameten (CLushed) Meceseeeeiee ee seteeat camino eee see ere eerste sere eet eer eae 0. 0175 Depth of the maxillary bono anteriorly..-------.--.--. -------=---+- joocg RASS Boas RUSE OASo coos 0.03 Depthvof the dentary bonelanteriorlyace. secre casein ee iol= a= elas) eicinel=le > Sbrosepbecedosa 0.015 men gthiotthecrovyn ofthownterioritootheeestecceiacemes eee etacis selects saree tactic 0. 006 Hengthrofthererowny ol wheysuperior: LOO tle criss ater ato etataye alate (atarei) ereleteliesa atm eee eel ele tae of eieaeesraimraae OL COAG Number of inferior teeth in 0™.01, 3; number of superior teeth in 0™.01, 4.5. “6 The vertebree are about as large as those of a fully-grown “ drum-fish,” Pogontas. From the yellow chalk of the Upper Cretaceous of Kansas, found on the Solomon or Nepaholla River, Kansas, at a point one hundred and sixty miles above its mouth, and in Trego and Rooks Counties, by Prof. B. IF’. Mudge, professor of natural science in the State Agricultural College of Kansas. SAUROCEPHALUS, Harlan. Leidy has pointed out the mode of implantation of the teeth in the typical species of this genus. The mode of succession of the teeth has not yet been indicated, but is well displayed in a specimen of the jaw of S. ara- pahovius, Cope. It is known from Harlan’s description that a large foramen issues on the inner wall of the jaw, opposite each root. The fractured ends of the specimen exhibit the course of the canal which issues at this foramen. It turns abruptly downward between the inner wall of the jaw and the fang of the functional tooth, and not far from the foramen. Its course is inter- rupted by the crown of the successional tooth. This is situated obliquely as regards the long axis of the jaw. It is thus plain that the successional appearance of teeth is different in this genus from what I have described in Portheus and Ichthyodectes. In them, the foramen is wanting, and the young crown rises within the pulp-cavity of the functional teeth, as in the Crocoditia. In this genus, on the other hand, 216 it is developed outside of the pulp-cavity and fang of the old tooth, and takes its place, as in many Lacertilia and in the Pythonomorpha, by exciting the absorp- tion of the latter. The conic form of these fangs in Saurocephalus is appro- priate to such a succession, and their great length seems to preclude the nutrition of the young tooth from their bases. The use of the foramina on the inner face of the jaw is thus made apparent, viz, the nutrition of the successional teeth from without. I cannot trace the canal below the crown of the young tooth to the base of the pulp-cavity of the old tooth; and there are canals in the jaw below the latter, one of which probably carried the dental artery. Species of this genus are less abundant in the part of Kansas examined by me than those of the preceding genera. ‘T'wo only have been observed up to the present time, as follows: SAUROCEPHALUS LANCIFORMIS, Harlan, Z. c. Medical and Physical Researches, 362; Leidy, Transactions of the American Philosophical Society, 1856, plate—Saurodon lanciformis, Hays, Transactions of the American Philosophical Society, 1830, 476. Established on a right superior maxillary bone, from a locality near the Missouri River. It differs from that of the other species in having a very elongate superior suture with the premaxillary bone, and in the very short dental crowns, which are as wide as deep. The largest species; known from the jaw only. SAUROCEPHALUS ARAPAHOVIUS, Cope. Established on a portion of a maxillary bone with a part of a suture, per- haps for attachment to a supernumerary maxillary. The size of the species is nearly that of S. danciformis, and the crowns of the teeth are rather short, as in that species, and less elongate than in D. phlebotomus. The teeth are very closely set, and the fangs are separated by very narrow septa. The crowns are expanded so that the edges overlap in some cases. The form of these is much compressed; width about equal to height; the edges convex and acute. The enamel is smooth and without facets. The roots are without the facets shown by Leidy to exist in S. danciformis, and appear to be longer than in that species, exceeding the length of the crown nearly four times. None are, however, perfectly enough exposed for complete measurement. As usual, there is a large foramen opposite each fang, below the inner alveolar 217 margin; and, between the latter and the series of foramina, the surface is slightly convex and minutely rugose. Measurements. M. Depth of the bone --.-. .-.--- 222-2. conan e oon = ve ea ee ne ee eo ne eee 2 9. 035 THTO ESS mh (Nie mae NG, Ge5e cp5d sogsas 0558 0 coSsn5 oFsiess be seSEE caaccs bosese Sodcus eaapee 0. 0055 Total lengtli of a tooth (2): ~~~... 2 oe nnn oe ene ie Bee ee ene en ee ne enn ee ween 0. 02 ILAAGINOPD OLOMMs sacceocusce Snoace Soesc0 HooHon onest Socase soDRSS OSDaSY DASEAd cooREeeONS - 0.0048 Vis OP GHOMWAN cose osooot cas0ce senor sabes sodore opades sa5Eds scones cescés osesoscoseas oSce 0. C035 Number of teeth in one inch, 8. The size of this fish was probably about equal to that of the Ichthyodectes anaides above described. The type-specimen was found loose on a bluff of blue shaly limestone, fifteen miles south of Fort Wallace. Kansas. ERISICHTHE, Cope. Proceedings of the Academy of Philadelphia, 1&72, p. 280. In this genus, the teeth are implanted in deep sockets as in other Sauro- dontide, and the subalveolar line of foramina seen in Saurocephalus is wanting. The crowns of the teeth are compressed and knife-like, as in Daptinus; but those of the anterior parts of the dentary and maxillary bones are greatly enlarged. Maxillary bone short, and rapidly tapering to a narrow edentulous extremity. Greater part of the dentary with a rugose band on the inner side of the teeth; its distal portion with a row of small compressed teeth, separating the large teeth into two areas. While this genus agrees with Portheus and Ichthyodectes in the absence of nutritious dental foramina on the inner face of the dentary bone, and especially with Portheus in the irregular sizes of the teeth, the crowns are compressed and knife-like, and closely similar to those of Saurocephatus. But the form of the maxillary is so different from anything known among Saurodontide as to render it probable that the genus pertains to another family-division. The Portheus angulatus, Cope, from North Carolina, perhaps belongs to the genus Evzsichthe, differing from EH. nitida in its greater size and less degree of compression of the crowns of the large fangs. ERISICHTHE NITIDA, Cope. Represented by numerous portions of a cranium with a fragment of a pectoral ray, discovered by Prof. B. F. Mudge near the Solomon River, i>) 28 C 218 Kansas. The ray is of the compound character already described as belong- ing to other genera of this family ; its edge is not preserved. The mazillary bones are subtriangular in form, and support three or four large lancet-shaped teeth at the middle of their length. There are no teeth beyond them; but, on the deeper side, there are several small lancet-shaped teeth. The outer alveolar edge is rugose. The teeth are very flat, acute, and perfectly smooth. The teeth on the greater part of the dentary are interme- diate in size between the large and small ones of the maxillaries; they stand on the outer edge of a broad horizontal alveolar plane. There are three large teeth in a series at the end of the dentary on the outer side; they have been lost, but their bases are broader ovals than those of the maxillary bone. On the middle line of this part of the dentary is a close series of small com- pressed teeth with striate enamel, standing on a ridge of the bone; they leave the last large tooth to the outer side, while on the inner side stand two or three lancet-shaped tusks of a short row farther back. Posterior dentaries o™™.10 apart. Measurements. M. hengthiofthemaxillary, boneiabovrsessoda bon bons Sob boudue BooGue Gonb Gadece aesSceeennones beesco 0.011 Teng thiosthe bases of five)proximal teeth ces sa. sere cise > nee mleenialnie sein wien aie eee slo em 0. 027 Width of the tongue-shaped bone at the middle........---....--.----- S8b 6 PHASED Ca nORC OCC SEnE 0.010 Depth of the dentary 2™™ from the end ......-...-. L9G. conoOO:DoOsoU abocal Gelato necscucace Sess 0. 012 From the Niobrara epoch of Trego County, Kansas. Discovered by Prof. B. F. Mudge, of the State Agricultural College of Kansas. Empo semiancers, Cope. Represented by numerous specimens of various individuals from the Kansas chalk. These embrace all the cranial bones in a fragmentary condi- tion, several vertebral columns, and scales. These belong to smaller individuals than those referred to the /. nepeolica. Characters of the species are to be seen in the pterygoid and larger mandib- ular teeth. The former are minute, and cover one side and margin of the bone en brosse without larger series. The latter have a cutting-edge on the posterior aspect of the apex as well as on the anterior. It extends but a short distance, while the anterior rises near the base, and is strongly convex. The tooth curves backward; the base is round in section. The convex pos- terior and inner faces are rather finely striate-grooved. The larger teeth of the external series are convex on the inner face; they are two-edged, and slightly incurved. The outer face of the dentary bones is strongly longitudinally parallel- sulcate. The inner face and the surfaces of all the other bones are minutely striate, exactly as in some of the Mosasauroids. The anterior extremity of the premazillary is straight on one side, and obliquely beveled on the other to an obtuse compressed apex. The bevel becomes subvertical posteriorly, supporting teeth much as in /. nepeolica. Two of its anterior teeth are a little larger than those that follow. The supposed pharyngeal is narrowed to 30 ¢ 234 a beak posteriorly, and presents an elevated longitudinal and obtuse ridge on the middle line. This supports a row of nine teeth, five of them having mates. The bone expands at the other end for a squamosal articulation with other elements. The pharyngeal teeth are smaller than the larger dentaries. The caudal vertebre are elongate, and much contracted medially; the rims of the cups are thickened, and the cups themselves very deep. There is a trace of a single median longitudinal groove. The neural and heemal arches are represented by broad longitudinal lamine in the specimens. The vertebrae are thus very different from those of the Saurodontide. In a second specimen, with jaws and vertebra, the pharyngeal bone is a tongue-shaped piece, wide and flat at one end, and contracting to a narrow apex, with subtriangular apex. A series of sixteen teeth and bases extends from near this point backward. The superior half of the dentary bone is almost smooth; the symphysis quite narrow and acuminate. The cranial bones are marked with radiating ridges, which are delicately denticulate. In a specimen represented by a nearly entire vertebral column, we count forty-three vertebra, of which twenty-three support entire haemal arches. The anterior two-thirds of these are the longest of the series; the centra shortening in both directions, most rapidly to the caudal fin. The middle part of the side of the centrum is entire on all but the last fourteen or fifteen, where it is marked by a deep longitudinal fossa. The dorsal cen- tra are marked with several narrow grooves and ribs laterally. There are three series of elongate diamond-shaped scuta on the sides of the abdomen opposite the dorsal vertebrae of this specimen. Their surface is radiate and concentrically rugose-sculptured. On the anterior caudal ver- tebrae, the neural and hemal lamin are higher in front of the spine than behind it. On the posterior dorsals, there is a short, slender process, project- ing forward from the middle of the centrum below, at right angles to the ribs. Neural spines and ribs slender. Measurements of No. 2. M. Length of theidentary, tothe twelfth larroitooth <- ~~. 22-- soaseeee seee eee eee eee eee 0. 067 Depthiof the dentaryatithe first Jarre tooth) 522s. ~~ ene ce ose eee nee ee eee ee Eee eee 0. 005 Depth ofthe dentary/at the tenthilarge tooth =<. -- --- 5 2. ooo woo nee ween ne nee eee ee ee AU SD) Depthiof the ? ptery soidsbone —- oon ee nsec w ene nine oe He a eae Bene en ee ee em SE Thickness of the? pterygoid bone. = 25. 2-2 sein cons een cose aec pee ac oe eee ee EO RSS Diameteriof the occipital cotylus=- ~~ <<< soo eens oo oo epee Oe ee ee) 0 Doueth of the four/anterior cervicals'. 032-02 = o- <<< sac nion oo once eee nce hoe ee Pan a) ss 239 Measurements of No. 3. M. Length of eighteen of the dorsal vertebra -.-..----- 2-2-2222 2 ene ne cere ee ce ee ee eee 0.275 engthyoreishteenvofthercaud alavertebreoeert qs ecisictsioetel =e [ale eteetoel= eiainysieieinie laaenic ere eeroete 0. 320 Depthyorthesheadtat thetopercul ariboxd Crs! eerie ten lelmteele leis = le elena alae elon aie On LoD ongitudmMalawitdthyotulreroperctluimesaeeres aeiseiectee ele renee arscte sia seleiee sere ee eee ae ONO SD, Length of theabdominal dermaliscutum)- = <2 ~---2-1-= -- -\6- ese sewa=isoeiseel---e- sec cere-se-c-e- 0,050 Widthroftherabdominalidermaliscutumbes sere ctecisiets sei seiiseeiimaciss ec enclserice se ecioneces 0.014 Numerous specimens from Professors Merrill and Mudge, and collected by myself during the expedition of 1871. PHASGANODUS, Leidy. The characters of this genus are as yet but little known; but isolated teeth may be knowa by the existence of a straight cutting-edge in front, and shorter one extending downward from the apex behind, to different lengths in the different species. The form is near to Hachodus, especially in the elongate anterior teeth; but, in that genus, the long teeth have unsymmetrical cutting-edges, which are not in the long axis of the dentary bone. PHASGANODUS CARINATUS, Cope. Founded on a shed example of one of the long teeth, taken from the matrix attached to the dorsal vertebrae of the Hlasmosaurus platyurus. The tooth is more elongate in outline than that of the S. spectosa, Leidy, ¢. ¢.; more than twice as long as wide at the base. The anterior margin is the more oblique, and its smooth face is margimed by a faint lune posteriorly, and is continued to the extremity. The convex inner face of the tooth behind is sculptured with a few fine deep grooves, which are separated by acute ridges, which do not extend over more than half the length of the tooth. Length, three lines. From the Upper Cretaceous of the neighborhood of Fort Wallace, Kans. PHASGANODUS GLADIOLUS, Cope. Represented by a single elongate tooth, which is intermediate in charac- ter between those of the two species last described, but much larger than either. It is large for an anterior maxillary tooth of Phasganodus anceps, and, should it pertain to the end of the mandibular series, will in so far resemble the genus Hnchodus; but the cutting-edges are opposite to each other, and not, as is usual in that genus, on one side, leaving the inner face very convex. In this species, the crown is rather slender, and compressed 236 above the base. The anterior cutting-edge extends to the bottom, while the posterior reaches only half-way down; there is no barb. The section of the base exhibits an angle in continuation of the latter. The inner face is a little more convex that the outer; its posterior half is rather coarsely striate-keeled. The posterior half of the outer face is finely striate. The inner posterior aspect of the root presents a cavity of absorption for the successional tooth, as in P. anceps. The cutting-edge and tip of apex are glossy black. Length from fossa, 0.019; diameter at fossa, 0™.006. From a locality at a short distance from the Phasganodus anceps. PHASGANODUS ANCEPS, Cope. Established on portions of a right maxillary bone of one individual, and perhaps the premaxillary of a second. The former supports six teeth and four empty alveoli; teeth on the maxillary. The maxillary has a flattened anterior termination, somewhat as in Stratodus apicalis; the superior face being excavated and widened, and gradually descending to meet the inferior. The line of junction, where also the premaxillary commences, 1s oblique from before inward and backward. The anterior tooth is a little larger than those following. The form of the teeth differs much from that seen in the species of Empo. They have an oval section at the base, but speedily become much compressed in a direction oblique to the long diameter of the bone, and develop cutting-edges opposite to each other, and separating equal faces. The crown is a little more convex on one edge than the other, and has a slight inward curvature. The apex is sharp. The cementum of the crown is smooth; but the surface of the basal portion below the commencement of the cutting-edges is minutely striate-grooved; some grooves being deeper than others; the surface having a silky luster. The inferior face behind the tooth expands gradually to its base, which is marked by the narrow cresceutic scar of the older tooth seen in Enchodus pressidens. ‘The crown of the tooth was scarcely as large as that of the maxil- laries, but is lost. Its basis is fluted, and the surface finely striate. Length of bone, 0”.015. This specimen was not found with the preceding. The latter was discovered on a bluff near Fort Wallace. The surface of the bone where preserved is without special sculpture. The upper margin is grooved for articulation with a supernumerary maxil- lary. Teeth in 0".01, two. Measurements. M. DCH Ot (Hie) IBS PAN MA WOON) so55cd e6Sedo Soe Sed deo ned debdee HeecoH Gobboo BeEbe6 ndeseo cacs 0, 008 Long diameter of the basis of the last maxillary tooth.......-.....-...---.------+------- ------ 0. 004 Depth of the maxillary bone at the basis of the last maxillary tooth........--....---.--.----.-- 0. 012 TETHEODUS, Cope. Premaxillary bone a petrous mass, without teeth; the maxillary with teeth in a single row, the anterior much enlarged; dentary with a single series, one anterior teoth much enlarged. Apices of teeth with trenchant edges. A genus chiefly differing from Hnchodus in the absence of the large tooth at the extremity of the premaxillary bone. ‘TETHEODUS PEPHREDO, Cope. Both premaxillary and portions of the maxillary and dentary bones of one specimen represent this species. They show it to have been a powerful fish, of the size of the Enchodus petrosus below mentioned. The premaxillaries are excavated by the usual three oblique fossee above on the inner side. The alve- olar face is a ridge extending obliquely across from a tuberosity on the inner side, behind the apical tuberosity. There is no surface for the attachment of a tooth, and no scar or other trace of the former existence of one. The maxillary underlaps it by an oblique suture, and supports a large tooth simi- lar to that at the end of the premaxillary in Hnchodus, behind which are seen the crescentic scars of the previously shed teeth. The outer face of the basal cementum of this tooth is perfectly smooth. The distal portion of the dentary bone is toothless ; its anterior tooth is a fang, with the base excavated in front; and an angle rising from the external side of it becomes a latero-exterior cutting-edge of the crown to the apex. The inner posterior, or more convex, face of the tooth is regularly and closely striate-grooved. On one dentary, there are three or four small denticles in front of it on the outer side. The smaller teeth have two cutting-edges, and the posterior face at the base is grooved striate. This regular grooving, as well as the large size of the first t maxillary, distinguishes this fish from the Phasganodus anceps. Measurements. M. Length of the premaxillary bone above....-.....-...-+--..--+-- LE ap racise ols eas asioe ee EES 0.075 Depthiofshespremasillaryaboncabovereseesseecer= see cocci sce nen eee SRO RE Rae ere 0. 033 Wadthrorthesbasisjat thenirstimaxillanyatoothver-neres sate scioacencensceeeceeeacemeccececescee 0. 010 M. Depthiorthemdentanyjat thevsixstitooth eerie ccetewcis sree apace se cles soeeiene mets eeeiennere eter 0. 020 Oa, Oe Hoe) Cle Minh Ay TO WIV) TibHSI WOON Eoon codele ss50 caus coeosus Becobeas obob eso: GosaccaD ce5e65 0. 020 ene chko tethers bitoot hesees ee mee eee ees eee eee eee at oLbeniecae caveaeeomesersaseees 0. 032 Intervalbetweenitheomaxillarysteobthissssacees eas: seine cee eo sa eee see eeles esas eee eee sem T OOS Niobrara epoch of Phillips County, Kansas; discovered by Prof. B. F. Mudge. ENCHODUS, Agassiz. The massive premaxillary bones of this genus are well known. They support an elongate fang at the anterior extremity. The maxillaries underlap them, and support some elongate teeth near their anterior end. The anterior -dentaries are also longer than the others. The teeth are all anchylosed by expanded bases; the posterior ones on an oblique alveolar surface. The long teeth are removed by an absorption set on fvot, at the posterior basis of each, which progresses until the crown readily breaks away. The successional teeth appear in front of the old ones, appearing successively as the animal increases in size, so that the scars of those of preceding stages are only indi- cated by successive curved lines, becoming more prominent from the back to the front of the bone. The posterior part of the cranium of FE. petrosus exhibits a supraoccip- ital crest with short basis; this element separates lateral pieces, which are epiotic or parietal. They are separated by a concavity from the bone that occupies the external posterior angle, which is epi- or opisthotic. On the inferior view, no muscular tube appears, nor any otic foramen, such as exists in the Saurodontide. The visible surfaces of the exoccipital, the pterotic, the postfrontal and prodtic, are subequal, and the alisphenoid is well devel- oped. A strong rounded ridge extends from the postfrontal angle to the anterior base of the prodtic, which bounds a deep fossa which occupies the point of union of the postfrontal, pterotic, and prodtic Cervical vertebrae are not codssified nor modified in any especial manner. Their centra are rough- ened with raised inosculating ridges. This genus has long been known from the Cretaceous of Holland and England ; two or three species have left their remains in the greensand of New Jersey, and others occur in the chalk of Kansas. Dr. Leidy described a species’ from the Cretaceous formations of the Upper Missouri region, which he called E shumardii. Several premaxillaries of a rather larger species were * Enchodus shumardii, Leidy, Proceedings of the Academy of Natural Sciences of Philadelphia, 1856, p- 257, is a smaller species than any of those here described. 239 oblained by my expedition; but the species is not determinable. The diam- eter of the basis of the tooth is 0".012. The long tooth of a species of medium size was detected, the Enchodus calliodon, Cope (Enchodus sp., Cope, Hayden’s Survey of Wyoming, etc., p. 424), in the matrix beneath the verte- bree of Elasmosaurus platyurus. EXNCHODUS PETROSUS, Cope. Established on numerous portions of cranium and yertebree of one indi- vidual, which had grown to the size of a twenty-five-pound muskallonge. The upper surface of the cranium is smooth, excepting along the inner border of the pterotic, where a narrow ridge supports two rows of small enamel tubercles. Numerous similar tubercles ornament the external face of the postfrontal bone. The premaxillary has the anterior margin truncate obliquely upward and backward; its lower margin passing into the base of the single large tooth. Alveolar surface elongate, posteriorly narrowed to an obtuse edge. The maxillary exhibits both borders obliquely truncate, with sutural face; the elveolar aspect supports two teeth, one larger than the other. (No. 2.) The premaxillaries are very massive, and exhibit, on their upper faces, _ three oblique fossee; the posterior transversely subdivided. External face smooth. Measurements. M. eng thi(distalkendylost)peees cesses eee ee ne ecleclc elec eniscioiecincisinceceisee esi eeeeciase eee On0G% Greatestiwidthiottheralveclartacemncc-cecontc seca se reat clos sees seen ese ee eee 0.018 Mepthiofsthelouterstacem sesso eee sae ae ieee eee eee oe hese eee eee rs seinem acacia 0. 030 Diameterotthey basis ofhostoothweemeactaseree see eis iciee oie ieee iio tee eniocceeriecoe 0. 009 Obtained by Professor Mudge from beds of the Niobrara epoch in Kansas. EncHopus poicuus, Cope. Represented by the premaxillary and adjacent parts of the maxillary bone with teeth, of a specimen of one-tenth the size of the preceding, and differing from it in the more slender proportions and the peculiar positions of the teeth. The premaxillary is long and narrow, and oval in section, supports one tooth (the large extremital one), and has two sublongitudinal fossee on the inner side above. Behind these is a fossa divided by inosculating ridges, and 240 a similar one on the outer side of the middle keel, which overlaps the two posterior ones. The maxillary underlaps farther than in some species, bring- ing the anterior teeth half-way between the large premaxillary and large max- illary teeth. In E. petrosus they are much nearer the large maxillary. Measurements. Length of the premaxillary ......-......---.--.---.------ SS806 c006 GéaSeGuacoan oSdede Sona deDS 0. 6270 Distance between the large maxillary and the premaxillary teeth. -...---.---..-..-...---.---. ransverseidiameter ofthe promaxillarys--= sseseser- cen alee eeeee eee eeeinetetacines cee eeeee : Transverse diameter of the large maxillary tooth The type-specimen of this species was originally described as pertaining to the genus Empo. ENcnopus CALLIopon, Cope. The tooth on which this species rests is especially elegant. It is quite slender, and gradually contracts to the acute apex. The cutting-edges, which extend to the base, are on one side, and are separated in one direction by a narrow, slightly convex, and perfectly smooth face. The inner face is strongly convex, being more than half a circle from the middle of the length down- ward. ‘This is also smooth on its anterior and posterior aspects; but, on the inner, there are nine sharp delicate keels, which disappear as the tooth con- tracts, the last terminating with the third quarter of the length. Total length, 0".02; longitudinal diameter at base, 0".0025; transverse diameter at base, 0".0035. The apex of the tooth is black. From near Fossil Spring, Western Kansas. ANOGMIUS, Cope. Proceedings of the American Philosophical Society, 1871, p. 170. This name was applied to a genus supposed to be allied to the Sawrodon- tide, and represented by vertebrae only. One species was named A. contractus, Cope, /.c., which was found by Professor Mudge. I have seen nothing resem- bling these vertebrae among either of the three families above described, and cannot ascertain their exact affinities without further investigation. It is clear that they are not referable to the known genera of Saurodontide nor of Stra- todntide. They present a marked character in the crowding-together of those caudal vertebrae which precede those that support the caudal fin. The centra are shortened, and the prolonged neural and hzemal arches and spines 241 lie one on the other, forming a fan-shaped body. The arches do not, at the same time, become anchylosed. his structure is seen in the A. contractus and in a second and smaller species. It finds a parallel in the caudal verte- ree of the genus Ischyrhiza of Leidy, from the greensand of the New Jersey Cretaceous, where all the elements of this fan-shaped bedy, centra, spines, etc., are codssified into a solid mass. This will define a family, and a species having the same structure is common in the Miocene of Maryland. in Anogmius, the sides of the centra, though lacking the large grooves of other genera, are striate-grooved and reticulate. So are those of Ischyrhiza, and both in this resemble the recent genus sox. ‘Add to this the fact that the teeth of /schyrhiza are almost exactly like those of Hsox, especially as to their large-fissured fangs, and half-pleurodont insertion, some relationship to the Hsocide may be predicated. I brought forward this suggestion as to the affinities of dschyrhiza in the preliminary monograph of the fossil fishes of ' Kansas already quoted. Anogmius contractus was about the size of Ichthyodectes prognathus. The second Anogmius is not more than one-third the size; the caudal vertebrz are more aggregated; and the neural spines, after leaning backward, are turned upward. The specimen came from Lower Butte Creek; no parts of cranium nor fins were found. The vertebra originally described by me as pertaining to Ichthyodectes ctenodon belong either here or to Ischyrhiza; they agree with the latter in most respects, having the neurapophyses codssified with the cen- trum. They are several times larger than those of A. contractus, and relatively shorter, being about equal to those of fschyrhiza mira, Leidy. I do not name these species, as they may belong to known genera, and will be, in any case, better identified from cranial and fin remains. APSOPELIX, Cope. Established on the remains of a fish preserved on a block of clay. It presents its ventral aspect, and displays pectoral, ventral, and anal fins, with the series of interneural spines to which the dorsal radii were articu- lated. The scales are large and cycloid. They do not present a trace of radii, but are marked with fine and close concentric grooves. These assume a vertical direction on the exposed surface, and are there more irregular; the dlc 242 more marginal ones terminating above and below. But few, 7. e., the central, grooves are truly circular. No abdominal carina. The two pelvic bones are together truncate heart-shaped, the acuminate apex presented forward. Their posterior portion is a strong transverse rib ; anteriorly, each is a thin plate, with thickened outer edge, uniting with its fellow on the median line. The median portion is so thin as to be readily broken away. The ventral fins are short and wide, with numerous rays. The coracoid bone is a broad lamina, and the pectoral fin evidently had the support of rod-like humeral bones of no great length, after the type of most physostomous fishes; but their form cannot be made out. Pectorals not elongate. The anal fin originates but a short distance behind the ventrals, and was not armed with an anterior spine; its length cannot be made out. Immediately above it, a dorsal fin, with slender rays, is represented by the bases of these rays. From above the yentrals to above the distal portion of the pectorals, a line of projecting points appears in the specimen, which Iam disposed to ascribe to the articular portions of the interneural spines and attached fin-rays of a first dorsal; but of this I cannot be entirely sure. The vertebree are longer than deep, and present the two deep lateral grooves frequently seen. The number of the cervico-abdominal series is twenty-six. The ribs are delicate, and supernumerary ribs are present. In comparing this genus with forms already known, points of distinction from all of them may be detected. Thus, the lack of pectoral spine will distinguish it from the known genera of Saurodontide at least. The character of the dorsal fin distinguishes it from Characinide, Salmonide, etc., which, with the scales, point toward Clupeide and Elopide. From these, the form of the pelvic bones distinguishes it. The end of both muzzle and caudal region are destroyed. The latter evidently contracts from the anal fin, and was not probably very elongate, but more as in Elops or Saurus. APSOPELIX SAURIFORMIS, Cope. Scales large; ten longitudinal series to be counted across the obliquely- depressed body. No lateral line visible. About seventeen transverse series between pectorals and ventrals. Ventral broad; when iaid backward nearly reaching anal, but far behind the pectoral. Anal probably rather short; but (his is not entirely certain. Radii, D.?—12, P. 16, V. 12. 243 Measurements. M. Length from the basis of Pectoral ray No. I. to Ventral ray 12............----- ---0 ee eens eee eee 0, 083 ene thy frombtheybasisjorwe we antOpAag emerreyciee aac ctcieissiaieciisceieiaicle seleleieeiec eee eiee eee ier nen 0. 0985 IL GWYEAAN GEES) WORT ITN cog oqoq0s coesOoIaUdabe dbusba codes Gose0s peed enuods codaSHBCoSconsands 0.0178 Widthiombthesventralefnidistall yaecemminceesciwatnelsteisbmciiseeincet ace cciccimeciceceenemesison ee. 0. 013 ILEMYSTIN OE TING) ERTS) O81D) Baasc cond Goap accuse Gesbo5 aSaqg0 SHdagaS sEnoUIEGHSe SheSnadcoacKEDd cae 0. 0168 WaGlan OWN lee hy oodcsn cooode bo0d Séacoo Gontanebcd ngadodocunesoobob Gag EcHoU aneo cpodadesopRbe 0. 047 Wadthrofstheipelvicibones\toretherteaccmencisceslssesctenecl-ceicisces sats incense ene sacio == 0. 016 Length of the pelvic bones together... -- 05. - oo. cece cena s cons cer ees concen enone Seea6 codenc 0. 016 The size of this species is. about that of a one-pound brook-trout. From the bed No. 2 of the Cretaceous of Meek and Hayden. Found in digging a well at Bunker Hill station on the Pacific Railroad of Kansas. SELACHIL. Remains of sharks and rays are far less abundant in the Cretaceous of Western Kansas than in New Jersey, and are much exceeded in abundance by the physostomous Actinopteri, as the present account. indicates. In the region near Fort Hays and Salina, sharks’ teeth are more frequently found. The cestracionts are, on the other hand, more abundant, since five spe- cies of Ptychodus Ag. have been found in No. 3; in beds in various parts of Kansas and Colorado. GALEOCERDO, Miill., Henl. GALEOCERDO CRASSIDENS, Cope. Established on two teeth of the type of G. aduncus, Agass., 7. e., with one cutting-edge much more convex than the other. The processes of the fang are rather narrow; that beneath the convex cutting-edge the most so. The apex of the tooth is very short, entirely plane, and stands over the middle or inner edge of the wider process of the fang. The shorter cutting-edge is straight or convex to near the base, where a short divergent heel develops itself The anterior edge is strongly convex, and all the edges are denticu- late. One side is more convex than the other. No denticles. Cementum smooth. Measurements. M. IL Gadi OWNS WEES) oscopcoouocacecce sé nca0s Soddd0 2UUORd codane SubSedouseeH Seeraplodesasaaocee 0.014 IEA GE UWA) GeO paGcad casooe paced doBeste BoDOdU COEEEa 000005 Hucabe Bobco9 CoeUEH sEcacdoadsud 0. 01 JeI ORG OS? 10.0 THO Bono cagG G68000 CAOEOO © OnnA cOOSd DAE OsS Bonecd docasy BAe oo OEeeadStbe GoGeus Gace 0.005 Wiidthiofthestoothiatithercontractioneesasascmiaseereeeclm alee caca cee e nice cere cc eiece eee enone 0 QJ 244 GALEOCERDO HARTWELLU, Cope. This species is of the G. egertonti group, 2. ¢, with the cutting-edges subequal and symmetrical. The basis is broad, and with convexities of the fang, instead of the processes of the last species. The external parts of the cutting-edge rise gradually from the base, and then more steeply at an obtuse angle. They are convex on each side above, and meet symmet- rically, forming a little less than a right angle. No denticles. Cementum smooth. Mdge everywhere denticulate. One side of crown plane; the other convex. Measurements. M. IES NNO EO NEUNSheae peaocomead pe ecd SSSA monocdnS Hease ceSao pacias Sagued sacacdan Koaaceboss 0. 0215 henge thyorsthe fan or oe arjem a oeiee emia nee osieie steeisiois eels one wien lee e cient ee cee eae comec eee 0. 0195 Elevationjofthoapex (from the:concayvity)is-- 5 -seee == sles sess woes eee eelcee eso e eee eae nee 0. 0145 Waidthvofthexcrown\ at the\contractionls .-. sa-6 sae isaerela ne ele= sei seni tree elaine see een ONO 2) This tooth is stouter and larger than that of G. egertonii, and was found beneath the bones of the Protostega gigas. It is named after Martin V. Hartwell, a member of my expedition, to whose acuteness and industry I owe many specimens. PTYCHODUS, Agass. PrycHopus JANEWAYII, Cope. Established on teeth resembling the posterior or pavement teeth of Heterodontus. Their arrangement cannot be described, as they are only known as separated specimens. Their surface is regularly convex, and covered with a dense layer, which does not exhibit pores, and is thrown into transverse or oblique ridges. No root is preserved in the specimens; but the basis is coarsely porous. A small tooth, probably lateral, is an oval, with its surface thrown into four folds, which traverse it obliquely from border to border. At the base of the outer, at one end, is a series of adherent tubercles; at the basis of that at the opposite end is a broken fold, with tubercles at its outer base. Length, 0.0045; width, 0".0025. 3. Cranium of Platecarpus curtirostris, side-view : the mandible viewed from the inner side. ae a Platecarpus ictericus, right dentary bone from the outside; a, surangular bone from the inside; | 7! b, inner view of fragment of left dentary bone; c, proximal view of the fragment. Ne + mn TORTOR. 2.CLIDAS tiie - Plate Ky. LATECARPUS CURTIROSTRIS. 4.PICTERICUS. WS. Geological Sucvey of the Ceeritories. late xiv. |. CLIDASTES TORTOR. 2.CLIDASTES STENOP» “ PLATECARPUS CURTIROSTRIS. 4.PICTERIGUS OI ii EXPLANATION OF PLATE x a vey i Occipital regions and suspensoria of Pythonomorpha, one-half natural size. Bs : Fic. 1. Platecarpus coryphaus : a, from bebind ; }, from before ; ¢, from below. Lae P } 2. Platecarpus ictericus : a, from behind; b, from below. = 3. Platecarpus curtirostris : a, from behind; }, from in front; ¢c, from below. PPEATHGARPUSCORYPHAEUG 2.P ICTERICUS. 3, P CURTIROSTRIS. EXPLANATION OF PLATE XVI : View of crania of Pythonomorpha, from above, one-half natural size. a ' Fra. 1. Clidastes tortor ; 6, premaxillary bone, from below. - - ; 2. Platecarpus mudgei, frontal and parietal bones. 3. Hl ateccrpus cor. uphaus, ponte bone only. Tre US a vie CAR PLATEG EES). TORTOR. (a Ww STE sLIDA 1k 6. C hi EXPLANATION OF PLATE XVII. Superior cranial walls of Pythonomorpha, from below and above, one-half natural size. ° t Fic. 1. Clidastes tortor, from below. 5 2. Platecarpus curtirostris, from below. 3. Platecarpus ictericus, from below. 4. Platecarpus ictericus, from above. 5. Platecarpus mudgei, from below. 6. Platecarpus coryphaus, from below. = 7 8. . Clidastes stenops, from below, without prefrontal bone. Pa. * . Clidastes stenops, from above, with right prefrontal bone. = * or 2. PLATECARPU )DON MUDGEI. 6. PLATECARPU JASTES TORTOR. 0 < 4 LI BR air & Son Th°s Sinc! ERICUS. TENOPS. > IC a WD ATECARPU PL 15..3 TIROSTR (a ise 1S) C able a C Ww IDA WS. Geological Survey ot the Treritories. Blate xvi. — The Sinclair k Son lith Phila CARPUS CURTIROS TRIS § PLATECARPUS CONPHAR YS, | CLIDASTES TORTOR. 2.PLATE -3-4, PLATECARPUS ICTERICUS 5. LIODON MUDGEI T8.CLIDASTES STENOPS EXPLANATION OF PLATE XVIIL. Vertebra of Pythonomorpha of three species, all more or less incomplete ; one-half natural size. Fic. 1. Column of Clidastes stenops, including some of the cervical, dorsal, lumbar, and caudal vertebra ; side view, beginning with the axis. : 2. The axis, from below. . : z Ae 3. Third cervical: a, from below; 6, from behind ; c, from in front. ee 4. Fourth cervical:a, from before; b, from behind; c, free hypapophysis. 7 5. A dorsal vertebra: a, from above; }, from below. 6. Part of vertebral column of Platecarpus ictericus, from the side; a dorsal vertebra from above. 7. Part of vertebral column of Platecarpus curtirostris. 8. The atlas of Platecarpus curtirostris: a, centrum; b, the neurapophysis from the front; ¢, from the inside; d, from the outside. ; a Se 1-5. GLIDASTES STHNG 7-8, PLATE CLR TERICUS. IC a WwW ARPU AG CURTIROSTRIS. B ofthe Cerri AW, §. Geological Survey Yilate xv aams STENOPS, 8. PLATEC 1-5 gLIDASTES STENOPS, FLANECARPUS rcrmRIG 7a, PLATECARFIS CURTIROSTRIg. i ie et ie a 0 Li ar ar l ; mr { { Fia. EXPLANATION OF PLATE XIX. Vertebra of Pythonomorpha: of Clidastes tortor and Platecarpus ictericus, one-half natural size. 1. Clidastes tortor, atlas centrum. ae 2. Ditto, axis: a, from the side; b, from behind. 8. Third cervical vertebra: a, from behind; b, from before; ¢, from below; d, from the side. 4. Cervical more posterior: a, from below, showing freé hypapophysis attached and crushed; b, from behind. : 5. Cervical vertebra behind the last figured, from behind; a, from before. 6. Rosterior dorsal vertebra: a, from behind; b, from in front; ¢c, from below. 7. Platecarpus ictericus, axis vertebra, from behind. 8. Third vertebra: a, from behind; b, from below. 9. A posterior cervical: a, from front; b, from below; ec, from behind. 10. Last cervical: a, from front; b, from below. 11 . Radius or fibula of a small Clidastes from Fossil Spring Canyon ; a, the inner edge of the same. 1-6. CLIDASTES TORTOR. 7-10. PLATECARPUS ICTERICUS. WeCLIDASTES. EXPLANATION OF PLATE XX. Vertebras of Pythonomorpha, one-half natural size: species, Platecarpus ictericus and Platecarpus co yphaus Tc. 1. Platecarpus ictericus, median dorsal vertebra: a, ftom behind; 0, from below; ¢, from front. — b.. Fias. 2-3. Platecarpus ictericus, lambar vertebra: a, from behind; 3, fiom below. These vertebrae wer found lying on their sides,and the form of the articular surfaces is slightly altered by Vite pressure. : : rly Fic. 3. Posterior lumbar vertebra: a, from before ; b, from below; ¢, from behind. z Platecarpus coryphaus, axis and third aD a, from mhesidee b, from below ; ¢, from behind. Neat ; 5. Three cervical and two dorsal vertebrae: b,c, d,and e, views from side, below, behind, and above, Rai ' respectively ; g,h,i, k,and 1, similar views of anotnen m,n, side and front views of an ante- — > rior dorsal. = 6. A posterior cervical from behind. : ~ A 7. Posterior dorsal vertebra: a, from below ; b, from above. aa * = VO) ot - dei ae Wat Pees i ey ao EXPLANATION OF PLATE XXI. Fic. 1. Posterior dorsal vertebra of Platecarpus corypheus: a, from front; 6, from behind. 2. Dorsal vertebra near the position of the last, from below. 3. Platecarpus tectulus,specimen from Butte Creek; middle cervical vertebra: a, vertebra, from above; b, from below. 4. Anterior cervical vertebra; 4 b, from below. 5. Cervical vertebra, more anterior; b, centrum, from below. 6. Anterior dorsal vertebra, from front; a, from above. 7. Platecarpus curtirestris, one-half natural size; a, axis, from behind; b, from below. 8. Platecarpus curtirostris, third cervical: a, from front; b, from below: c, from behind; d, from above. Fics. 9-11. Anterior dorsal vertebra of the same species: a, views from front; 6, from behind; c, from above. Fig. 12. Median dorsal, from the front. 13. Posterior dorsal: a, from front; b, from behind; ¢c, from below. 14. Clidastes cineriarum, Cope, postero-median dorsal vertebra: a, from front; 0, from behind ; c, from below; d, from the side. 15. Lumbar vertebra: a, from the side; b, from behind; c, from below; d, from above. 16. Anterior candal vertebra: a, from front; b, from side. ; 17. Palatine tooth, natural size. TE CLUES. 14-17 CLIDASTES CINE RIARUM. D 336: RUS. RYPHA EGARPUS GO URTIROSTRIS al \ { EXPLANATION OF PLATE XXII Clidastes planifrons, Cope, one-half natural size. Fic. 1. Superior view of parts of cranium preserved, including parts of the parietal (a), postfrontal (%), : In both figures, a is the coronoid, b prefrontal (d), and fronto-nasal (c) elements. 2. The same, seen from below. 3. Posterior part of left mandibular ramus, without angle. 4. Median portion of right mandibular ramus, showing hinge. the surangular, ¢ angular, d articular, and e splenial. 5. Portion of the right quadrate bone: 5, proximal part, inner view; 5 a, proximal view of the ? +] same; 5 b, external view of the same. 6. Distal morta of left quadrate, external view ; 6 a, internal view ; 6 b, posterior view. 7. Right palatine bone, from below; 7 a, right palatine bone, from outer side. 7 : CLIDASTES PLANIFRONS. ty ATS teeves: © o i — Seale ot — Va a _ ie Oe : EXPLANATION OF PLATE XXIII. Fiaes. 1-14. Clidastes planifrons, one-half natural size. Fic. 1. Right ueurapophysis of the atlas. 2. Axis, with odontoid bone, hypapophysis of latter wanting; 2 b, the same, inferior view. Fics. 3-6. Cervical vertebra in order; a, free hypapophysis, proximal surface; 0, inferior, c, anterior, d, superior, and, e, posterior views of the same. Fics. 7-13. Some of the dorsal vertebrae in order; 7 b, the (?) first dorsal from below; c, from in front; and, e, from behind; 13 b, a posterior dorsal from below; ¢, front; e, posterior extremity. Fia. 14. Basi-occipital and part of sphenoid, from below. 15, Exoccipital, from above and behind. Fies. 16-18. Sironectes anguliferus, one-half natural size. Fic. 16. ? Third cervical from above, exhibiting zygosphen. 17. Last cervical, displaying zygantrum; zygosphenal articulation indistinct, through error of artist. 18. Terminal portion of the articular bone from the outside, showing the suture with the sur- angular. U.S. Geologierl Sevey of the C = Plate XX. 1-15. CLIDASTES PLANIFRONS. 16-18. SIRONECTES ANGULIFE RUS. 2 EXPLANATION OF PLATE XXIV. Fias. 1-14. Sironectes anguliferus, one-half natural size. - 1-2. Two consecutive cervical vertebre, the ? third and fourth followed by an interval, from which one or two vertebrae are missing; inferior view. 3-5. Five consecutive cervical and dorsal vertebrae, seen from below: 3, last cervicals; 4-5, ante- rior dorsals. Like 1 and 2, these have suffered somewhat from depression. Fia. 6. A free cervical hypapophysis; a, proximal view. Fics. 7-12. Vertebree from the anterior portion of the caudal series which bear diapophyses, commencing with the more anterior; 7 a, front; 7 b, posterior view of 7; 8 a, inferior view of number 8; 10 a, inferior view of two candals (fig. 10), with broken chevron-bone on the anterior; 12 a, anterior, and, b, posterior view of 12, a distal one of the series. 13-15 Ribs: 13-14, proximal, and, 15, median portions. UL, S. ealagient Survey ofthe Cerviturte: E TRY) Sanclau & Son dite Phila DRONE CIES ANG ULI EAU Ss: EXPLANATION OF PLATE XXV. -Vertebra and limb-bones, ete., of Platecarpus ictericus, from Professor Mudge’s collection, one-ha’f natu-_ tal size. From figs. 1-25 belong to one individual, and figs. 26-27 toasecond. = Fic. 1. Scapula. : ; ; 2. Fragment of coracoid. oe 3. Humerus: a, from outside; l, from proximal; c, from distal end. : 4. Radius. 5. Carpal bone. - ae ie 2 Tics. 7-10. Supposed metacarpals, with (6 a and7 a), their distal extremities. (aa ; 11-20. Phalanges, with, a, their proximal, and, dD, their distal extremities. Fig. 21. A cervical rib. | Sees 22. A dorsal vertebra, viewed from behind. ns 23. A dorsal vertebra: a, from the side; b, from below; ¢, from the front. 24. The palatine bone, from below. ; ; ‘ 25. Ulna of a second specimen. : 26. Metacarpal of the same. Da tries Le ee = {| je v +t uy Q TLV ) CARPU! nia L aay PLAT Fie. 1. — EXPLANATION OF PLATE XXVI. Figures of vertebrae and limb-bones of Pythonomorpha, one-half natural size. A series of 28 caudal vertebre of an undetermined species, taken from Butte Creek bluffs ; the series is continuous except a definite interruption at the.15th, and two or three possibly in front of it: a, posterior surface of 28th vertebra; b, posterior surface of 24th vertebra; ¢, posterior surface of the 21st vertebra; d, the same, from the front; ¢, the 13th, from behind ;_ J, the 13th, from the front. Many of the neural spines indicated by outlines are preserved on separate pieces of rock. . Platecarpus ? mudgei, specimen from Fox Canon: a, posterior part of mandibular ramus from within, one-half natural size ; b, posterior part of right dentary, natural size: ¢e, posterior part of left dentary, natural size; d, coronoid bone, one-half natural size, from the outside: ¢, coronoid bone, one-haJf natural size, from the inside. . Platecarpus mudgei, from Professor Mudge’s collection, original type: a, hypapophysis of axis, from below ; b, hypapophysis of axis, from behind; ¢,centrum, or basal part, of atlas; d, articular extremity of scapula. . Middle dorsal vertebra of Platecarpus crassartus, Cope, from Protessor B. I’, Mudge’s collection, profile: a, from front. . Adjacent vertebra of same, profile: a, from front; b, from behind; ¢c, from below. . Lumbar vertebra: a, from behind; b, from below. . Anterior caudal vertebra, from front. . Caudal with diapophysis: a, from behind; b, from below. . Humerus of Platecarpus crassartus: a, from within; b, from without; ¢, proximal end; d, distal end. . Femur of same: a, from within; b, from without ; ¢c, proximal, and, d, distal extremities. Fibula of same: a, from side; b, proximal; and, c, distal extremities. . Phalange of same. 3. Cervical vertebra of Platecarpus glandiferus, from Professor Mudge’s collection : a, from front; b, from behind; c, from below; d, profile. . Cervical vertebra of the same from Butte Creek: a, from front; b, from behind. = a — PLAT. CRASSARTUS mevep ofthe Ceveitarics 5 VS. Gealagical EXPLANATION OF PLATE XXVILI Fic. 1. One cervical and five dorsal vertebrae, with a rib, of Platecarpus latispinus, in place, one-half natural size ; from Professor Mudge’s collection; profile. 2. Last cervical and first dorsal, from below. 3. Last cervical vertebra from front. 4. Sixth dorsal: a, from front; b, from below. 5-10. Platecarpus tectulus, specimen from Professor Mudge’s collection from near Sheridan, one-half natural size. 5. Median cervical vertebra from front. 6. Median dorsal vertebra: a, centrum, from above; b, from front. 7. Atlas neurapophysis, from within. 8. Quadrate bone: a, from outside; b, from inside; c, proximal end of fragment. 9. Frontal bone, fragment, from above. ’ 10. Parts of angular and articular bones with cotylus of mandible. 11. Third cervical vertebra of Liodon dyspelor, the Fort Wallace specimen, from behind, one-half natural size. LL, S$. Geological Survey ofthe Cevvitortes, rc The Sinclair & Son ith Phila Pea PRATH CARP Us LATISPINIS. S10, Pl. THeorTuUnus: ily LIODON DYSPHLOR: me . Left ramus mandibuli, posterior portion: a, surangular; b, articular; ¢ and d, splenial bones; . Coronoid bone, from within. . Cranial bone, ? postfrontal. . Hypapophysis of odontoid: a, from front; b, from back. ; . Hypapophysis of axis: a, from above; b, from below; somewhat distorted by pressure. . Hypapophysis of a median cervical vertebra. . Premaxillary and part of maxillary bone of Liodon proriger, in profile. . Premaxillary bone of Liodon proriger, from below. EXPLANATION OF PLATE XXVIII. Cranial and vertebral bones of Liodon dyspelor and L. proriger, one-half natural size. ; . Liodon dyspelor, left maxillary bone. é, articular extremity of angular; /, articular extremity of splenial. (USumvey of the Cex tries, 1-7, LIODON DYSF ayia i UWS. Geological Survey oF the Territories, ; late 2xvM. 7. LIODON DYSPBLOR- 8-9. LIODON PRORIGER + _ p * ' aaa ‘ Sart x vu. ir “ % f Fy pew, 4 im, r E * n 2 ay * . A : / Ata! ; = x ' = wh i 5 EXPLANATION OF PLATE XXIX. Vertebre of Liodon dyspelor, from Butte Creck, one-half natural size. They are selected from various = points in the column, the best-preserved being preferred ; most of the dorsal and caudal vertebra are omitted. : Fig. 1. Atlas and axis from the side : a, centrum of atlas ; b, neurapophysis ; ¢, hypapophysis ; d, centrum of axis, free hypapophysis omitted (see Plate xxviii, fig. 6). : 5 2. Last cervical. ; 3. A posterior dorsal. 4. A lumbo-sacral, with its posterior face upward, with neural arch on right, and diapophysis on left side. S Fics. 5 to 6. Caudal vertebrae. _ LIODON D | ELOR COPE, late XXIX. wenep ofthe Ceveraries S .Hcalogwal S Vi LIODON DYSPELOR COPR, Vr Vertebra of Liodon ay yspelor, from Butte Creek, and L. proriger, type-specimen, one-half natural size. G EXPLANATION OF PLATE XXX. 1. Third earvicall vertebra of L. dyspelor, from below. 2. Fifth cervical vertebra, from behind; slightly distorted by pressure. 3. Middle cervical, from behind. 4, Last cervical: a, from behind; b, from below. 5. Anterior dorsal vertebra: a, from front; b, from rear. 6. Middle dorsal, centrum from bebind. 7. Posterior dorsal, centrum from behiud. 8. Posterior dorsal or anterior lumbar: a, from behind ; b, from below. 9. Three consecutive lumbar vertebra, from below. - 10. Cervical vertebra of Liodon proriger, from the front; belonging with the remaining figures to | fig. 14, inclusive, to the type-specimen in the Museum of Comparative Zodlogy, Cambridge. 11. Anterior candal vertebra of the same individual, from behind. 12. Median caudal: a, from front; b, from the side. 13. Posterior caudal vertebra: a, from front; b, from side. 14. Four distal caudals, profile. ’ ] {| IDNGS) 121 IONE x 4 LIODO Bes ‘ Cs ISOF retturies, Le © 10-14. LIODON PRORIGER. atural Size. Plate x aK A, S. Gralogical Snvey of the Ceeeitortes. 1-9. LIODON DYSPELOR W-u. py one half Nalural Size ODON PRORIGER. EXPLANATION OF PLATE XXXI. Fiaes. 1-3. Vertebrae of the Liodon dyspelor from Butte Creek, one-half natural size. Fig. 1. Atlas and axis from the front, the odontoid bone wanting: a, axis; b, neurapopbysis of atlas ; c, basal element of atlas ; d, hypapophysis of the odontoid. 2. Axis, posterior view. 3. Third cervical vertebra, from behind. 4. Six caudal vertebre of Liodon dyspelor, consecutive, except an interval between the third and fourth ; one-third natural size. Of the anterior three, the diapophyses of the left side are broken off, and the neural spines, being turned to that side by pressure, are displayed. From the specimen figured in Plates xxvii-xxx. 5. Centrum of a lumbar vertebra of Liodon dyspelor, from behind. From the type-specimen in tho Museum of the Smithsonian Institution, fronr Fort McRae, New Mexico. LIODON DYSPELOR. EXPLANATION OF PLATE XXXII. Shoulder-girdle and anterior limb of Liodon dyspelor, from preceding specimen, one-half natural size. Fig. 1. Scapula; a, articular extremity. 2. Coracoid. 3. Huwerus: a, from inside; b, from outside; ¢, proximal; d, distal articular extremity. 4. ?Ulna: a, from side; b, proximal; d, distal extremities. KS. Geological Survey ofthe Ceevitaries, lite KAKU. LIODON DYSPELOR. a A : i jo - ; _ ' Ae 7 on) nee - a , J ris : 7 ory os i. : ha o i - Tt 4h or) : wi Y iy : bs 7 : Ta ; io (i A 1 7 1 | 1 Re + P 5 2 . . i e A s 6 id P * 2 zt “ » : - 4 3 ioe ; ae M = EXPLANATION OF PLATE XXXII. Pelvic arch wiih posterior limb and some cranial fragments of the same specimen of Liodon dyspelor, one- half natural size. f Figs. 1-5. Pelvic arch from above: 1, right ilinm from above ; 2, left ilium from side; 3 and 4, right and left ischia in normal relation: 5, pubis, distalend. - : : 7-9. Right side of pelvic arch, bones separated: 7, ilium ; 8, pubis; and, 9, ischium. Fic. 10. Femur of the right side, found in place: a, outer; b, inner sides; ¢, proximal; d, distal extrem- ities. 11. Fibula, found with candal vertebra: a, from side; b, proximal; and, ¢c, distal extremities. 12. Tibia, found in matrix close to the fibula; a and b, extremital faces. Ties. 13-14. Metapodial bones; a and b, extremital views. 15-26, Phalanges, with accompanying extremital views. Tic. 27. Probably exoccipital bone with part of condyle and suspensorium. 28. Probably part of parietal bone, showing foramen and base of areh. Fics. 29-30. Teeth ; a, sections of crowns. Fs = . id i 3 a , ‘ :. (= - ‘ ; ; : ; , é 7 - ; 3 . : r ni ; . = ; : = 7 ' — » j ee ‘ ’ i & Fy a : ’ . ; . ’ - ‘ 3. > UES, vat Werer tige ot oe LIODON DY Plate XXXII. [Survey ofthe Cervitories. Hi, §. Gralogres _} TRY Sinclair & Son lith Phila LIODON DYSPELOR COPR. ———— SC 7. os ‘, EXPLANATION OF PLATE XXXIV. Fias. 1-42. Series of dorsal, lumbar, and caudal vertebrae of a species of Liodon, obtained by Professor Mudge, one-half the natural size. The only hiatus is in the caudal series, where prob- ably three vertebra are wanting between Nos. 16 and 17. a 1- 5. Dorsals, from above. ; 6-12. Lumbars, from above. ae ; = 13-23. Caudals, from above. : ; 24-42. Caudals, from the side, except Nos. 31-35, which are viewed from below. TL, S, Healagreal Suvey ote Ceeettaries, if terre LIODON SPRope AD _ i) a as EXPLANATION OF PLATE XXXV. Fiaes. 1-8. Vertebre of Liodon (figured on preceding plate), one-half natural size. 1-6. Inferior views of lumbar and caudal vertebra at transition-region, from No. 10 to No. 15. Fic. 7. Cup of dorsal No. 1 (Plate xxxiv); 7 a, ball of dorsal No. 1. 8. Ball of another dorsal. 9. Caudal vertehra No. 33, posterior view. 10. Caudal vertebra No. 42, anterior; a, posterior views. lias. 11-14. Liodon nepaolicus, Cope, one-half natural size. lic. 11. Quadrate bone from outside; a, from inside; b, proximally ; d, distally. 12. Profile of premaxillary bone (broken), and adjacent portion of maxillary; a, premaxillary from below; b, maxillary from below. 13: Mandibular ramus of left side from within, with apex broken off: Ar., articular bone; ae angular; S. Ang., surangular; Cor., coronoid; Spl., splenial ;.D., dentary. 14. Odontoid process, superior view. 15. A ? posterior dorsal vertebra, somewhat modified by pressure, from below; a, posterior articular: face, 16. Quadrate bone of Clidastes planifrons, postero-interior view, one-half natural size. LS. dhealoatert Suey ofthe Cervituri yd. GCovalagrert Surrey ofthe Covertartes a’ y oth urtes, ate OKRY. The? Sinclair & Son lath Phila. 1-10 LIODON SP 1-15. LIODON NEPAEOLICUS. 16. CLIDASTES PLANIFRONS. A EXPLANATION OF PLATE XXXVL Palatine bones of Pythonomorpha, one-half natural size: a, from the outside ; b, from the inner side . ¢, from below. Fic. 1. Liodon dyspelor. 2. Liodon proriger. 3. Clidastes tortor. 4. Clidastes stenops. 5, Platecarpus curtirostris. 6. Platecarpus coryphous. a 7. Platecarpus ictericus. > ' WS, Gealagtent Suevey of thy Tervitartes, tube OOXKVIL, LILODON DYSPELOR 2. blODON PRORIGHR. 3, ChIDASTES TORTOR, 4.¢. STHNOPS. 5. PLATE CARP US CURTIROSTRIS "6 P CORYPHALUS 7° Pi1CTERICUS: era Wire Vee ere oe ee aig) EXPLANATION OF PLATE XXXVILI. Quadrate bones of seventeen species of Pythonomorpha. From figs. 1 to 11, one-half natural size; figs. 12 to 17, one-third natural size. In all, fig. a represents the external side; fig. b, the postero-internal, or internal view ; fig. ¢, the proximal; and, fig. d, the distal articular faces. In figs. 5, 10, and 13, the angles and ridges are indicated as follows: a is the “knob,” or the ridge homologous with it ; p, median posterior ridge; y, the distal internal longitudinal ; 6, the internal longitudinal, or simply the internal ridge; e¢, the proximal internal angle; ¢, the alar process. Bi Vic. 1. Clidastes propython. : 2. Clidastes tortor. Clidastes stenops. : Liodon validus. In fig. c, the internal angle of the proximal articular face is turned to the left Tt should be turned to the right, in order to correspond with figs. @ and b, and those of the. other species. Moreover, the posterior hook and alar process are broken away. 5. Liodon dyspelor. i 6. Liodon proriger, flattened by pressure. 7. Platecarpus mudgei. 8. 9 fee . Platecarpus ictericus. . Platecarpus coryphaus. 10. Platecarpus curtirostris. 11. Platecarpus tympaniticus. 12. Mosasaurus depressus. 13. Mosasaurus fulciatus. 14. Mosasaurus giganteus. 15. Mosasaurus maximus. 16. Mosasaurus dekayi. 17. Mosasaurus oarthrus, 5 i tio 2 —_— a ae . ay ’ a Fs - = \ a " i ‘ > = : ’ : ‘ ’ = ‘ < ‘ . % i K ~ *s ra 2 i = a] = \ i 1 \ = : “ - i 7 ‘ P — © — : ¥ : 7 “ i a 7 44 = WS. Geolasierl Survey of 6 QUADRATE BONES. OF PYTHONOMORPHA. 12> 17 AN LIODON. 7-1. PLATECARPUS 7, Plate XXXVI US. Grological Sunvey of the Covritories QUADRATE BONES. OF PYTHONOMORPHA: }2.CLIDASTRS, 46 | 12-17, MOSASAURYS AODON, 7-11. PLATECARPUS EXPLANATION OF PLATE XXXVIIL Restorations of crania of three species of Pythonomorpha, viewed from above, one-third natural size: : g Pmx., premaxillary bone; Mz., maxillary; Prf., prefrontal; I’r., froutal; Pof., postfrontal; Pa., ee parietal; Pro., prodtic; Lxo., exoccipital; Opo., opisthotic; Sq., squamosal. Fig. 1. Platecarpus curtirostris. 2. Clidastes tortor. 3. Clidastes stenops, parietal region inferential. U.S. Geological Swnvey of the Cervitortes. late XXXVI | | 1. PLATECARPUS CURTIROSTRIS. 2.CLIDASTES TORTOR 5, CUDA is» elllanOerss EXPLANATION OF PLATE XXXIX. Cranium of Portheus molossus, Cope, type-specimen, natural size; the maxillary and mandibular arches . ; separated from their normal positions, so as to display the teeth and articulations. UL, S. Geological Suevey ofthe Cereitories. Ulnte MNXIK. EXPLANATION OF PLATE XL. Portheus molossus, one-half natural size, from the type-specimen (See Plate xxxix). Fic. 1. Mandibular ramus, from the inner side. . Palatine bone, with malleolar body, from above; 2 a, from the outer side. . Selerotic ossifications from the outer side ; 3 a, from inner side. . ?Hyomandibular from the outer side; 4 a, from the inner side. - Quadrate bone, including the symplectic. . Preéperculam. . ?Interopercnlum. Tics. 8-9. Uncertain bone wo 10 Ol & LW. S. Gealogicnl Smmey ofthe Cevvitartes, § Sanclair & Son lth P _ 2oRInE US) Monocgsus EXPLANATION OF PLATE XLI. Cranium of Portheus molossus, Cope, nine-sixteenths natural size: second specimen figured 184. : Ne 512 PORTHEUS MOLOSSUS COPE, R Fia. 1. Maxillary and palatine arches of Portheus lestrio, from Trego County, Kansas: FIGs. EXPLANATION OF PLATE XLII. displaying the ‘premaxillary, maxillary, ethmoid, prefrontal, sclerotic, palatine, malleolus, ectopterygoid, pterygoid, and metapterygoid bones. One-half natural size. Lower part of scapula, with adjacent parts of clavicle; the former with inferior articulation of pectoral spine; one-half natural size. 3. Upper part of the same scapula, showing two superior articular facets and two posterior fossa. for basilar bones. f 4, External view of the pectoral spine and rays, and scapula of Portheus-like Saurodont, the artic- ulation slightly dislocated to show the three facets; one-third natural size. 5. Internal view of the inferior part of the scapular arch of an allied species, exhibiting the scap- ula and coracoid and foramen inclosed by them, the three facets, and two cotyli; one-half natural size. 6. Apsopelic sauriformis, Cope, type-specimen from Brookeville, Kansas. 7. Tooth of Lnchodus gladiolus, natural size; a, section of base, natural size. 8. Scales of a Clastes, from the Milk River, Saskatchewan, natural size; a, edge-view. 9-10. Lamna macrorhiza, Cope, from Rooks County, Kansas; DEERE size. 1 11-12. Lamna mudgei, Cope. ) PORTHEUS LESTRIO. 4-5. SCAPULAK ETC. 6. APSOPELIX SAURIFORMIS. 7 FNCHODUS GLADIOLUS. 8.CLASTES. 9-10. LAMNA MACRORHIZA. [1-1a. L. MUDGE , ‘ EXPLANATION OF PLATE XLII. ie a Portheus thaumas, Cope, parts of one specimen from Butte Creek, Kansas. Fia. 1. Basioccipital, parts of hyomandibular and preopercular, with the symplectic aud quadrate bones 2 in relation ; natural size. atid i 1a. The same piece to the middle of the hyomandibular bone, viewed from the inner side ; ov the = hyemandibular are seen fragments of the superior branchibyals. / mee 2. Premaxillary and maxillary bones of the same; the latter broken off near the middle. 2a. Inferior view of the same, displaying the bases of the teeth. 3. Superior aspect of the dentary bone. : 4. Sclerotic bone of same. ee eS ~ U.S. Geologienl Cervitories, PORTHEUS THAUMAS. EXPLANATION OF PLATE XLIV. V'tas. 1-4. Portheus thaumas type, natural size. Vic. 1. Part of vertebral column. 2. Terminal vertebrx, with hemal and neural spines supporting caudal fin; a, first fan-shaped hzmal spine. 3. First fan- -shaped hzmal spine, viewed from Abores 3 a, the same, proximal articular face. 4. Marginal rays of caudal fin. 5. Fragmentary pectoral spine of the type-specimen of Portheus molossus, Cope. Fas. 6-9. Ventral spines of a Saurodont, found together, species unknown: 6, the first; 7, the second ; 8, third; a, opposite side of same; 9, basis of one more distal. 10-11. Scapula of Portheus molossus, type-specimen ; inverted. Fic. 12. Pectoral spine of Pelecopterus gladius ; a, from anterior edge. 13. Pectoral spine of Pelecopterus perniciosus ; a, from posterior edge. 14. Part of vertebral column of type of Ichthyodectes anaides, Cope, found in Dosttion natural size. 15. Vertebra of the same specimen. Cervtturies, PORTHEUS THAUMAS., 5.1011 P MOLOSSUS: 6 14-15. IGHTHYODECTES ANAIDE Q Rove Wate AULT. UW, S. Geological Suey ofthe Cerviteries. : 3 . - : CaS . ea ,._— ma ae - = = =: I-A: PORTHRUS THAUMAS. 6,101 P MOLOSSUS.69° PORTHEUS INDET 1415 ICHTHYODECTES ANAIDES. EXPLANATION OF PLATE XLV. Fras. 1-8. Ichthyodectes anaides, Cope: figs. 1-4 and 6, one-half natural si size; figs. 5,7, and 8, natural size; from one, the type-specimen (see Plate XLIV, fig. 14). Fig. 1. Mandibular rami, lying on a block of yellow chalk. 2. Premaxillary bone, outer side. . Premaxillary bone, inner side. Right maxillary, outer side. Sclerotic bones of the same. a‘ ; Hyomandibular, symplectic, and quadrate bones. y 4 A ATLA PE SE 1 ay Femoral bones, from below; 7 a, from behind. ' Pectoral spine. ae Fics, 9-11. Terminal caudal eeeore of Portheus molossus, from above; a, from front; b, from side. f 12. Jaw of Bryactinus amorphus, Cope (p. 282), natural size: a, profiler b, masticating face ; ¢, oppo- site border. From the greensand of New Jersey. ‘ PAST Ew TAWA a LSuevey ofthe Ceerttartes, a TTT OTT AEE Aa ae Ne =i RCTES ANAIDES. 9-12. PORTHEUS MOLOSS 13 BRYACTINUS AMORPHUS. l Wes EXPLANATION OF PLATE XLVI Fias. 1-4. Ichthyodectes ctenodon, Cope, natural size. Fic. 1. Maxillary bone, from the outside. 2. Dentary bone, from the inside. 3. Hyomandibular bone. 4. Cervical vertebra. : 5. Ichthyodectes hamatus, Cope, natural size: 6, premaxillary and maxillary bones, from the outer side ; 5 a, mandibalar ramus, from the outer side. Fias. 6-10. Ichthyodectes prognathus, Cope: 6, the premaxillary, with anterior extremity of maxillary, from the inner side; 6 a, same, from the outer side; natural size. 7. Ventral spine accompanying the same, natural size. 8. Cervical vertebrx, one-half natural size. 9. Dorsal vertebra, one-half natural size. 10. Terminal caudal vertebra, with articulating spines; one-half natural size. 11. Maxillary bone of Pachyrhizodus kingii, from the inner side, natural size. 12. Three vertebra of Anogmius, largest species, accompanying remains of Ichthyodzctes ctenodon, one-half natural size. 13. Cervical vertebra of a ? Portheus, one-half natural size. ee CTENODON. 5. ILHAMATUS. 6-0. I 12. ANOGMIUS. 1 TDA CTI De Ea Be Lazar Vd DAT ll. PACHYRHIZOD Fia. 1. ~ i) onaonans EXPLANATION OF PLATE XLVIL. Muzzles and crania of Saurodontida, natural size. Inferior view of vomer and ethmoid bones of Portheus lestrio, Cope, obliquely depressed, display- ing cotyli for the maxillary and premaxillary condyles. ees . Inferior view of vomer and ethmoid of an unknown species, not distorted. . The same view of Daptinus phlebotomus. . Superior view of the same specimen. . Profile of an unknown Saurodont. . Superior view of ethmoid of Daptinus phlebotomus, Cope. . Inferior view of cranium of Portheus ? arcuatus. . Superior view of the same cranium. . Palatine bone, with malleolar body, of Portheus arcuatus, from the outer side. Pa a EXPLANATION OF PLATE XLVIII. Fic. 1. Base of pectoral spine of Pelecopterus chirurgus, displaying the prone (a, b) and slender (¢, dG, 0) basilar bones, with fossz for the inner ones; f, coraco-clavicular foramen. — ea) = ee 2. Base of pectoral spine of Pelecopterus perniciosus ; lettering as in the preceding figure. aeolian a Fics. 3-8. Erisichthe nitida, Cope, probable maxillary, premaxillary, and other bones. + att, Via. 6. Distal end of dentary bone, from outside; a, from above. ae 7. ? Hyomandibular bone. Plate XLVH. Eat ERY ae | eae EXPLANATION OF PLATE XLIX. Fias. 1-4. Daptinus phlebotomus, Cope, natural size. Tie. 1, The mandibular and palatine bones compressed in one mass, viewed from above; la, thes sane © from below. ey ie : 2. Maxillary and superior lamina of Rear acillaey bones of the left side, from without; 2 a the samo, a ge from the inner side. The longitudinal lines represent fractures only. * Re ace ae 3. Right dentary bone against the palatine; the latter wit» malleolar process Broken off. 4. Left dentary. 5. Part of maxillary bone of Saurocephalus arapahovius, Cope, natural size; inverted by artist. 6. Palatine bone of Stratodus apicalis, Cope, outer aspect, natural size; 6 a, same, inner side. 8. Premaxillary and part of maxillary bones of the same, natural 3 8 a, same, from below; 8 b, teeth of the sume, enlarged. 9. Distal extremity of premaxillary bone of Empo nepaolica, Cope; ; type-specimen. Li, S. eal agteal Sravey ofthe Cort lon Oy UROCEPHALUS ARAPA sabes ODUS APICALIS. 9. EMP0 NEPAEOLICA. EXPLANATION OF PLATE L. Figs. 1-4. Pachyrhizodus caninus, Cope, natural size. Fig. 1. The mandibular rami, the right one with the angular bone entire behind, and Dror enp in front ; _ the left with the angular process broken off. 2. The right angular, viewed from the outer side. - 3. The right premaxillary bone, inferior aspect ; 3 a, viewed from the outer side. 4. Right maxillary, inner side: 4 a, same, from above. | 5 3 ; = 5. Distal part of dentary bone of Pachyrhizodus latimentum, Cope, ir om outer side. 6. Premaxillary bone of Ichthyodectes multidentatus, Cope, from within ; 6 a, same, from without. 7. Part of the maxillary bone of the same. . 8. End of dentary bone of Lmpo nepewolica, Cope. ; ; All the figures on this plate are of the natural size. 5 SA amet LATIME NTUM. Oy les 1-4. PACHYRHIZODUS CANINUS 6-7. ICHTHYODECTES MULTIDENTATUS. ae ao valsh Wecaey Vis, She EXPLANATION OF PLATE LI. Fias. 1-7. Pachyrhizodus latimentum, Cope, three-fourths of natural size. Fig. 1. Ortarmswp Both mandibular rami, the upper without articulo-angular bone ; the lower with the upper edge downward, and the distal end of the dentary wanting; 1 a, symphyseal extremity of the left dentary ; 1 b, probable accessory maxillary bone. . Supposed predrbital bone. Element of uncertain position. . Supposed hyomandibular; on the same block as the next — fig. . Supposed interoperculum. . Uncertain piece, perhaps symplectic. . Lateral view of a vertebra accompanying the same. . Pachyrhizodus leptopsis, Cope, mandibular ramus, natural size: a, distal half of dentary bone, from within; b, proximal part of the same bone; ¢, vicw of distal or symphyseal end of the same. Heolagierl Survey of the Cervituries, 1-7 PACHYRHIZODUS LATIMENTUM. 8. Plate un. 4 = . a ' = . . ( 2 mo ‘ . < . Sees aan = =e 7 #-° — - a a “ ~ ; ~VGe - a wt) + 1 ‘ >, ‘ 5 ~ ie a ; x 7 = 1 : ‘ ' 7 7 i 3 re - - \ y 2a ‘ + i tae ; me. ee + . a - em : 5 _ eh ~< > 7 = : r =e Fs <1. oe cs : = 2 % a F ~ -a _ ( = = om. 5 Pe Le eS ee - i" - : ™ . \ ~- a! m Are> ae o ’ _ 1 EXPLANATION OF PLATE LII. Fic. 1. Empo nepeolica, Cope, head and anterior part of the body, on a block of the chalk of the Niobrara . beds, from Professor Merrill’s collection: a, b, right premaxillary and dentary bones; c, d, left premaxillary and dentary bones; e, frontal bones; f, ectopterygoid; g, quadrate; h, dermal scuta; i, pectoral fin; one-half natural size. : 2. Pelecopterus perniciosus, Cope, spine of pectoral fin, one-half natural size. 3. Pectoral spine of Pelecopterus gladius, Cope, one-half natural stze; from Professor Mudge’s col- lection. a 4. Beryx insculptus, Cope, from Dr, Lockwood’s collection, one-half natural size; a, scales, natural size. UL, § .Hcalogteal SS 1. EMPO NEPAEOLICA. 2. IGHTHYODECTES PERNIG PEI piss paeieo, Se ie PORTHEUS’ GLADIUS: 4.BERYX INSCULPTUS ALS. Groloaical Survey of the Cevritories. Hlat = ° plea LTT 1. EMPO NEPABOLICA. 2. IGHTHYODECTES PERNIGIOSUS. 3, PORTHEUS GLADIUS 4. BERYX INSCULPTUS EXPLANATION OF PLATE LIIL. Fic. 1. Vertebral column, with pectoral fin, and impression of opercula of Empo semianceps, Cope, one- half natural size; an interruption between the dorsal and candal series is not filled by the specimens: 1 a, obverse of the piece containing last dorsals, showing dermal bones. 2. Opercular, hyomandibular, quadrate, and angular bones of another specimen of Empo semianceps one-half natural size. : Fics. 3-5. Parts of a single specimen of Hmpo nepeolica. Fic. 3. The mandibular ramus, natural size, from the inner side; 3a, the same, from the outer side; 3 b, the angle and cotylus, from bebind. 4. Premaxillo-maxillary bone of the same, natural size, viewed from below. * 5. Cervical vertebra and basioccipital bone of the same, from below, one-half natural size. Ties. 6-9. Portions of a skeleton of Hmpo semianceps, natural size. Fic. 6. Dentary bone, from the outside. 7. ? Pharyngeal bone, with dental alveoli. 9. Dermal scuta. Fics. 10-13. Empo merrillii, Cope, natural size. 11-12. Premaxillary bone, from below. Fic. 12. Proximal end. 13. Pharyngeal bone, with alveoli. Figs. 14-17. Lmpo contracta, Cope, natural size. Fic. 14. Pharyngeal bone, with alveoli. 15. Premaxillary and maxillary bones, from below. 16. Proximal side of premaxillary, from the side. 17. Dentary bone, from outer side. US. Geologient Survey of th i-2. EMPO SEMIANCEPS. 35. RMP 10-13. EMPO MERRILL Plate win. NEPAROLICA. 69.EMPO0 SEMIANCEPS. 14-17 EMPO CONTRACTA. U, S§. Geological Survey of the Territories. = _. Pte Th Sunclair & Son lith Phila 2. EMPO SEMIANCEPS. 3-5. EMPO NEPAROLICA. 6-9. MPO SEMIANCEPS. 10-13. EMPO MERRILLIL 4-17 BMPO CONTRACTA Oeil oraif A ce pee ee ae Par =~ ea ee EXPLANATION OF PLATE LIV. Fignres natural size, except fig. 9, which is three-fourths nature. . Premaxillary and part of maxillary bones of Tethcodus pephiredo, Cope, natural size, from the outer side; a, same, from inner side; b, same, from lower side. . Distal end of left dentary bone of the same, outer side, in natural relation with fig. 1. . Distal end of right dentary, from outer side; a, from above. . Left premaxillary and part of maxillary bone of Enchodus petrosus, Cope, from the inner side; a, same, from outer side. . Distal end of left dentary, from inner side, in relation with fig. 4; a, the same, from above. . Base of posterior part of craninm of the same: a, basidccipital; b, exoccipital; ¢, opisthotic; d, pterotic. . Premaxillary and part of maxillary bone of ZLnchodus dolichus, Cope, from outer side; a, same, from below. . Scapula of Pelecopterus chirurgus, exhibiting the facets for articulation of the two large and six slender basilar bones. i Ne) ee a oe oe a ee -~ tf See ‘ zs EXPLANATION OF PLATE LY. Restorations. 1. Portheus, one-fourteenth natural size. 2. Clidastes, one-twentieth natural size. 3. Platecarpus corypheus, outline of the imperfect cranium of the type-specimen. UL S, Geological Survey of the Cereitories.. e * 1_PORTHEUS: 2 CLi@AvS tiie: Blsrte shy. zs Tiger WEAK w SS Z 1 SN x I Ws SA’ GREEE REATECARPUS CORYPHAEUS US, Geological Survey of the Cereitories. * *- : Blate iy. r m ie ae ‘ ] Lu Th WM lg KEK BEEK SI44: T7242 NY BR ERREELEKELKLC PEL TA LEELA LL ERALELAAY TAAL CAA TTA cam NR Se 1. PORTHEUS. 2.CLIDASTES. 3.PLATECARPUS CORYPHAEBUS. ane ta . 59 EXPLANATION OF PLATE LVI. Haploscapha grandis, Conrad, one-third the natural size; two specimens (figs. 1 and 2), (see page Fig. 2 a. Cartilage-pits of external dorsal border of No. 2. 3. Hinge of a third specimen, the right-hand end broken 01). os ttaries een DIS RAN] i‘ = HAPLOSCOPHA ant Yate poe oly EXPLANATION OF PLATE LVIIL. Haploscapha eccent ica, Conrad, one-third natural size; the extremity of the hinge-border broken off. Fic. 1. Internal view. 2. Outer side of the same shell, covered with Ostrea congesta. JTGLNADOH VHdOOSOTdVH ¢ h V at Nig}: y a SSID) a) {hy 0 (Q QU y i UL oy BINDER, &9W. Market St.. ieee Wilkes-Barre, Pa. 4 — i lh ! | 00054 noc asc asresresrearnorebrnneanencaasen neescnnrasnuten tua Rae IEAM RIERICS ATAAERATR DENCY ION 3 hn I SMITHSONIAN INSTITUTION LIBRARIES | 4: