AND ATES OF NORTH AMERICA. 



145 



LYTOLOMA JEANESII, Cope, Spec. Nov. 



Tliis turtle is known by two marginal bones, the nuchal with its suture for the first vertebral distinct, and the 

 first with the usual divergent suture for union with the, nuchal. A second specimen, which T owe to the liberality of 

 John Meirs, was taken from the lower part of the upper Greenland bed at Hornerstown, Monmouth county, N. .T. 



It shows its relationship to the Catapleura repanda in the narrow proportions of the nuchal bono, which thus 

 resembles an ordinary marginal, and differs entirely from the form in Chelydra and Clielone. Another point of simi- 

 larity is the union of this bone with the first marginal by a coarse gomphosis, the process pertaining to the latter. 



Its marked peculiarity is the normally narrow and free first, and therefore second marginal bones. The first 

 gradually narrows inwardly, and is bordered by a regular, slightly concave, free margin. Its suture with the nuchal 

 is straight : its suture with the second lias the entering angle near the outer margin seen in C. repanda, P. sopita, 

 etc. The rounded margin of the nuchal is not heavy; that of the first marginal is more so than in 0. repanda, and 

 increases near the posterior suture. 



An indistinct SCUtal suture crosses the middle of the marginal; but whether the marginal scuta arc narrower than 

 the bono, cannot lie determined. The line separating the first vertebral from the nuchal descends, or narrows the 

 nuchal scutum, but not so rapidly as in 0. repanda,, being straight instead of concave. 



The first marginal bono is three-fifths as wide as long in the, present species ; in the 0. repanda four-fifths as wide 

 as long. 



Width nuchal marginal, 

 Width " scutum, 



Width first marginal, 



.Linen. 



10.5 



8.5 



15.5 



The Hornerstown specimen furnishes portions of several costals, and three marginals, with the head of the 

 humerus. They were taken by the writer from the green sand, in natural relation; they indicate an animal of as 

 large size, as the Osteopygis emarginatus, and demonstrate that the characters on which this genus rests, although 

 those of immature Ostcopygos, are nevertheless those of adult animals. 



The superior margin of the first marginal is entire, and rather thin, showing its complete separation from the 

 carapacial disc. The outer margin is somewhat thickened, and the proximal extremity exhibits the usual wedge- 

 shaped articulation. Length exteriorly, 8| in.; width, 1 in. 5 1. A lateral marginal, perhaps the sixth, is remarkable 

 for its narrow form, and the nearly equal measurements of the three chords of its transverse section. The external 

 face is thus very oblique and the margin not at all recurved, or in any way cmarginato. The rib pit is round conic'. 

 Length, I! in. I) 1.; external face, 1 in. lin. wide; internal chord, 1 in. 5 1. The inferior and superior inner margins 

 are alike, thin and acute. Width of a costal bone, :i in. 6 lin; depth near sutural margin, !! lines. Diameter humeral 

 condyle, 1 in. Clin. The oostal bones are without sculpture. 



Discovered in the upper green sand-bed or the upper Cretaceous, near Barncsboro, Gloucester Co., and 

 Hornerstown, Monmouth Co., N. J. 



This species is named after Joseph Jeanes, of this city, an active and liberal member of the Academy of Natural 

 Sciences of Philadelphia. 



LYTOLOMA ANGUSTA, Cope. 



Chelone sopita, Leidy. Cretao. Kept. U. S. Smithsonian Coutrib., XII., p. 105 (Second Specimen), Tab. 

 XIX., fig. 2. 



Posterior and lateral marginal bones, with the upper margins, not produced beyond the lower. The second with 

 a deep, open emargination, the length twice the average breadth. Width of fifth .5 length, the superior surface con- 

 cave; vertebral scuta wide, angles produced. 



This species is at present indicated by a mandible and some marginal and costal bones. These are, however, so 

 characteristic and different from anything hitherto observed in the Cretaceous Green Sand of New Jersey as to de- 

 AMERI. 1MIIL0S0. S00. — VOL XIV. 37 



