372 



NATURE 



[August 14, 1890 



was originally referred by Count Miinster, and afterwards 

 by Agassiz, to the class of fishes, under the genus Pla- 

 codus; but more perfect specimens enabled Prof. Owen, 

 in 1858, to show that this animal was really a reptile 

 which probably fed upon shell-bearing mollusks and used 

 its flat, broad, palate-like teeth, so thickly-coated with 

 enamel, for pounding and crushing their shells (see Phil. 

 Trans., 1858, p. 169). 



Two genera, Placodus and Cyamodus, are referred to 

 this group, at present known only by the skull and teeth, 

 no vertebras or bones of the pectoral or pelvic girdles, or 

 limbs, having been as yet discovered. Owen originally 

 referred this singular form to the Sauropterygia, but sub- 

 sequently he regarded it as belonging to the Anomo- 

 dontia, in which order Seeley also places the Placodontia. 

 The present author, however, assigns the Placodonts to 

 no ordinal position, a course which, we think, is to be 

 regretted. If not Anomodont reptiles, why not give 

 them the value of an order .? Surely they have as good a 

 claim to such a position as Proterosaurus ? 



Fig. 2. — Left lateral aspect of skull of Galesaurus planiceps, Owen; from 

 the Karoo beds (Triassic), South Africa. (^ nat. size.) a, an upper cheek- 

 tooth ; b. an incisive tooth. 



Fig. 3.— Right lateral aspect of imperfect cranium of Mlurosanrns felinus 

 Owen ; from the Karoo beds (Triassic), Beaufort West, South Africa. 

 (I nat. si^e.) a, upper incisive tooth ; b, upper cheek-tooth, enlarged. 



The Anomodontia, which follow next in order, are a 

 truly Triassic group, and have been met with in Russia, 

 India, North America, and in South Africa. It is espe- 

 cially from this last-named region that the British Museum 

 collection has been most largely recruited, the majority 

 of the specimens having been procured by Messrs. A. G. 

 and T. Bain, Dr. Atherstone, and Sir George Grey. 

 Quite recently. Prof. H. G. Seeley, F.R.S. (assisted by 

 the Government Grant Committee of the Royal Society), 

 visited the Cape, where he was most successful in ob- 

 taining a large series of reptilian remains, not yet fully 

 worked out, but of which sufficient is already known to 

 justify us in believing it Will prove one of the most 

 valuable additions made for years past to our National 

 Museum. 



The interest attaching to these South African Triassic 

 rocks (if Triassic they be) lies in the fact that they have 

 yielded evidence of one of the earliest mammals known — 

 Tritylodon — represented by a most remarkable although 

 imperfect cranium, with dentition similar to Cope's genus 

 Poly mastodon, from the Eocene of North America. 



NO. 1085, VOL. 42] 



In the group of Anomodont reptiles are included 

 several forms having a well-differentiated series of cheek- 

 teeth, canines, and incisors, a character of dentition con- 

 sidered at one time to be peculiar to the Mammalia. 

 Good examples of such dentition may be seen in the 

 skulls of Galesaurus, ^lurosaurus, Lycosaurus, &c. 



Another no less singular family, placed in this ord^r, is 

 that of the Dicynodontidse, in which the surface of the 



Fig. 4.' 



-Lateral view of the skull of Dicynodon lacerticeps, Owen ; from 

 the Karoo series, South Africa. 



palate and mandible are without teeth, the skull being 

 provided with a pair of tusk-like maxillary teeth, growing 

 from persistent pulps ; the alveolar margins of the jaws 

 being trenchant, and probably encased in a horny beak- 

 like sheath, as in Hyperodapedon. 



Another remarkable form of Anomodont, from these 

 Reptiliferous beds of South Africa, has been referred to 

 the genus Pariasaurus by Owen. In the form of its 



Fig. 5.- 



-Palatal aspect of cranium of Empedias molaris. Cope ; from the 

 Permian of Texas, North America. (J nat. size.) 



head it is very like a huge Salamander, 8 to 10 feet in 

 length, having a numerous and uniform series of 

 moderately tall marginal teeth in its jaws, with swollen 

 and narrow crowns, ornamented with a few deeply- 

 marked flutings descending from the cutting edge, and 

 with numerous small conical teeth on the palate. The 



