Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/125

1869.] gigantic Saurian, which, in virtue of the mass and hollowness of its limb-bones, is allied to Iguanodon and to Megalosaurus, and will belong to the second division of my Saurian system. None of its allies has hitherto been found so deep in the European continent, nor from rocks of so great age. These remains belong to a new genus, wbich I term Plateosaurus; tbe species is Pl. Engelhardtii. I shall hereafter publish a full account of the fossils."

The fuller account which Von Meyer promises is contained in that splendid monument of palæontological genius and industry, the 'Saurier des Muschelkalkes,' which came out between 1847 and 1855. The remains enumerated consist of a few imperfect fragments of a cranium without jaws or teeth, six more or less fragmentary separate vertebræ, an imperfect sacrum (consisting of, at fewest, three ankylosed vertebræ), fragments of ribs, and several limb-bones. The centra of the vertebræ are nearly four inches long, and the most perfect limb-bone is about sixteen inches long.

This bone is represented in tab. 69. figs. 1–3 of the work cited. Von Meyer appears to be inclined to consider it a tibia, comparing the smaller end of the bone to the distal end of the tibia of Poikilopleuron; and the figures support the determination. The other figures on the same plate (4, 5) represent the distal end of a femur, the posterior face of the outer condyle of which exhibits the remains of the ridge which plays between the tibia and the fibula, and is so characteristic of the Dinosauria among reptiles.

In the summary of results at the end of the 'Saurier des Muschelkalkes,' the following paragraph occurs (p. 162):—

"As to the family of the Pachypoda, with their colossal massive forms, it is certain that it is to be met with in the Upper Keuper, where it is represented by the two genera Belodon and Plateosaurus, each having one species, B. Plieningeri and P. Engelhardtit. These are different from the Pachypoda of the Oolite and the Chalk,"

And further on, at p. 163:—

"Concerning the other Saurians, with flat, cutting teeth, which are comprehended under Cladyodon, Thecodontosaurus, Palæosaurus, and Zanclodon; it has not yet been made out to what family they belong, nor whether they are allied to the Pachypoda or not. They appear in rocks which occupy the horizon of the lower 'Grenzbreccia,' and therefore appear to represent a Muschelkalk which is passing into the 'Lettenkohl;' they occur besides in the actual Lettenkohl and in the Keuper. The North-American genera Clepsysaurus and Bathygnathus appear to be allied forms."

It will be observed that Von Meyer here reckons Belodon among the Pachypoda. The study of the more complete remains of Belodon, described in the 'Reptilien aus dem Stubensandstein des oberen Keupers' (Palæontographica, Bd. vii. 1861), however, led to a different conclusion, which is thus expressed (l. c. p. 346):—"Hence Belodon was no Pachypode; if Plieninger has declared it to be such, it is because he has mixed up the remains of two totally different animals. Belodon was plainly more of a crocodile than of a lizard."

The researches of Prof. Plieninger referred to by Von Meyer are