ART. II.-DESCRIPITONS OF FISHES FROM THE CRETACEOUS AND TERTIARY DEPOSITS WEST OF THE MISSISSIPPI RIVER. BY E. D. COPE. TRIÆNASPIS VIRGULATUS, Cope, gen. et sp. nov. Character genericus.-Shape anguilliform; vertebræ elongate, contracted medially, furnished with wide and short diapophyses over the abdominal region. Cranium elongate, not beaked; jaws furnished with acute teeth of moderate size (but small number in the typical specimen). Dorsal fin short, median in position, its radii cartilaginous. Ventral fins entirely behind dorsal. Caudal and anal fins unknown, the latter probably wanting. The dorsal and ventral surfaces each protected by tripodal shields. Shields of other forms on the sides. This, with the genus following, introduces for the first time into the North American extinct fauna the family of the Dercetiform fishes. The relationship of the family has been discussed by various authors, especially by Pictet and Von der Marck. The former regards them as Teleostei; the latter as "Ganoids". As I do not adopt the division signified by the last name, I find Professor Pictet's view nearer to the point. The specimens indicate further that the Dercetida belong to the Actinopteri, and probably to the order Hemibranchii. The only alternative is the order Isospondyli, and the characters which separate the two are not clearly shown in the specimens. Distinct bones below the pectoral fins may be interclavicles, which belong to the Hemibranchii. As compared with the other genera of this family, Trianaspis differs in the very short dorsal fin and posterior position of the ventrals, with the probable absence of the anal. The scuta differ in form from those of some genera. Character specificus.-The head is relatively large and the body slender. The fins are all small. The rami of the mandible do not present a long symphysis. The opercula are subround, and the bases of the pectoral fins are quite posterior to them. The dorsal and ventral scuta are triradiate, the median branch of the three being directed anteriorly. A series of smaller triradiate scales extends along the superior lateral region just below the dorsal row, and there is a similar one above the abdominal row on each side. Between these and the vertebral axis there are numerous narrow, band-like scuta, directed backward and toward the vertebræ. Radii: D. 9 or 10; P. 12 or 13; ventrals disturbed. Vertebræ: to first ray of dorsal fin, 27-28; from dorsal first ray to opposite base of ventral fin, 10. The dorsal and ventral scuta correspond in 112mber to the vertebræ. Measurements. Le Dgth of portion of fish preserved.. length of head Width of head behind..•• •• • the M. 0.121 0.030 0.008 0.0035 0.0070 0.0070 0.0040 This fish was discovered by Dr. F. V. Hayden, Geologist-in-Charge of Cretaceous horizon of Dakota. This species agrees with the type-species of Leptotrachelus of Von der Marck in the position of the ventral fins beneath the dorsal, in the great elongation of the anterior vertebræ, and in the lanceolate form of the head. It differs from that species (L. armatus v. d. Marck) in its more elongate dorsal fin, in which it approximates the genus Dercetis. Two incomplete specimens represent this species, neither of which possesses the caudal nor exhibits an anal fin. In one of them, the cranium is preserved in a somewhat dislocated condition at the extremity of its very long peduncle. The vertebræ of this region, which might be called a neck, are several times as long as those of the dorsal series. The femoral bones are slender, and commence below the anterior part of dorsal fin. In one specimen, the ventral fin originates below the twelfth dorsal ray; in the other, below the fifth. As the latter is the least distorted, I suspect the fin to occupy its normal position. The dorsal radii are slender, and the middle and anterior longer than the posterior; they number twenty-seven in one specimen, and nineteen in the other, where the posterior portion is broken away. The ventral rays are hair-like, and do not extend to the line of the distal end of the the dorsal. The pectoral fins are well developed, and occupy their usual position. The cranium is much dislocated, but the snout is acute and attenuated. The dermal scuta consist of median, dorsal, and ventral rows of tripodal form. There are some slender, longitudinal, hair-like bodies on the sides, which cross the ribs. The vertebræ present the characteristic elongate centra. The diapophyses are longer on the postventral than on the preventral region. Each scutum is as long as a ver tebra. Length of neck of No. 1 Measurements. Length of neck to base of dorsal fin.......... Length of base of dorsal fin Elevation of dorsal fin... M. 0.045 0.071 0.025 0.009 Discovered by Dr. F. V. Hayden in the Niobrara Cretaceous of Dakota. This fish is particularly welcome, as displaying generic identity with a species of the Westphalian Chalk, and with a third, from the Slates of Mount Lebanon. It thus indicates a closer relation between these faunæ than could be predicated on the discovery of the family to which it belongs. The horizon of Mount Lebanon has been regarded as Eocene, but Heckel and Von der Marck place it in the Upper Cretaceous. To the conclusion of these paleontologists, the discovery of this and other species described in this paper lends support. ICHTHYOTRINGA TENUIROSTRIS, gen. et sp. nov. Character genericus.-Head attenuated and produced into a beak; jaws with weak teeth, of equal lengths. Dorsal fin small, composed of soft rays. Body covered with small, round scales. Vertebræ sub elongate. The specimens representing this genus are so far imperfect that the caudal and anal fins remain unknown. But they show clearly that it differs from the genera which appear to be related, namely, Dercetis and Rhinellus, in the absence of dermal scuta and in the short dorsal fin. But one species has come under my observation. Character specificus.—The dorsal fin is about half as far behind the cranium as the length of the latter. It is supported by well developed interneural spines; but these elements do not exist in front of it. Muzzle very slender, the mouth apparently opening to behind the orbit. The scales closely imbricate, in about twenty longitudinal series, above the vertebral line of the side. Dorsal radii, II. (rudimental), 12. The superior supplementary ribs are numerous. From Cretaceous No. 3 of Dakota (Dr. F. V. Hayden). SPANIODON SIMUS, sp. nov. M. 0.043 0.061 0.006 0.010 0.005 0.006 Another genus of the Lebanon is represented in the collections from Dakota by a rather abundant species. The elongate anterior teeth of the dentary bone and the edentulous maxillary are exhibited by the new species; but I am unable to find the long premaxillary teeth said to exist in the typical species of Spaniodon. As the absence of these may be due to accident, and as all other characters coincide, I leave it under this genus. From the known genera of Saurodontidae of the same horizon, the edentulous maxillary bone, combined with long dentaries with round section, and the absence of pectoral and ventral spines, separate it. To the characters named, I may add that there are no dermal. scuta, but cycloid dorsal scales. Whether the body was scaly below the lateral line is not clear from our specimens. There are numerous slender branchiostegal rays. The pectoral fins are inferior; the dorsal is not large, is composed of soft rays, and is submedian in position. The ventral fins originate behind it, and the anal fin still more posteriorly, leaving a long abdominal cavity. The ribs are long, and the superior ribs numerous. The femora are elongate, and are narrowed and converging anteriorly. They do not appear to be fissured. The dorsal centra are not elongate, and are grooved. Character specificus.-Three specimens, more or less mutilated, represent this fish; one of these is almost entire, and serves as the type of my description. The gape of the mouth is wide, and is directed forward and upward. The extremity of the muzzle is the premaxillary bone, and this is concave backward, so as to give, with the oblique mouth, a bulldog expression. The superior profile is gently concave. The opercular apparatus is produced slightly downward and backward, so that the posterior depth of the head equals its length. The partly opened mouth displays two long, straight, acute teeth on the anterior extremity of the dentary bone. The pectoral fins are large, while the ventrals are small. The anal is moderate, and has a concave border. Radii: D. 11. 20; A. II. 14; V. 8; P. 14. Vertebræ: D. 32; C. 13. Anterior dorsals not different from the others. This species is referred to a genus established by von der Marck for three species of Isospondylous, and probably Clupeoid fishes, which have been found in the Upper Cretaceous of Westphalia. They present mostly negative characters, resembling Clupea, without abdominal nor cephalic serration, and with minute teeth. The fishes here referred to this genus do not exhibit any teeth; but as my specimens, five in number, are small, it is not certain that adults may not display them. The presence or absence of teeth is not a constant character in all Clupea, according to Günther. Leptosomus v. d. Marck does not appear to me to differ from Sardinius. The Sardinius nasutulus is a small species of moderately elongate form, with a rather long head and protuberant muzzle. The dorsal fin originates in front of the middle of the body, and the ventral fins take their rise immediately below its anterior rays. The anal originates behind the line of the dorsal, but far enough forward to leave an elongate caudal peduncle, which is also quite stout. The pectoral fins reach nearly to the base of the ventrals. Radii: D. 9; A. 11, about; V. about 8. The boundaries of the scales are difficult to define on the specimens, but there do not appear to be more than eight or ten longitudinal series. Their sculpture consists exclusively of concentric grooves. There are fourteen dorsal and fifteen caudal vertebræ, all with long and slender neural spines. Of the former, five are anterior to the first inter neural bone, which is directed downward; the last caudal vertebra is slender and turned upward. The scales are very much attenuated, so that their number cannot be made out. The ribs are stout for the size of the fish. The superior surface of the head is rather narrow, and tapers with straight borders to the muzzle. Measurements. Length of head (including operculum) Depth of body at middle of caudal peduncle.... Niobrara Cretaceous No. 3 of Dakota (Dr. Hayden). SARDINIUS LINEATUS, sp. nov. M. 0.0115 0.0175 0.0170 0.0280 0.0410 0.0055 0.005% 0.0010 0.0065 0.0050 Two specimens of similar small size constitute the basis of information respecting this species. Many characters can be derived from these; but the dorsal fin being absent from one of them, and the ventrals and posterior part of the body from the other, the mutual relation of these fins is not ascertained. The form is very elongate, and the head is lanceolate. The dorsal fin is distant from both cranium and caudal fin. The fins are composed of slender rays, and the anal is not elongate; the caudal is deeply forked, and no vertebræ are included behind the basis of its external rays, although four are embraced within the convergent lines of the anterior upper and lower fulcra. The ver |