1908.] ON THE ARMOUR OF EXTINCT REPTILES. 605 



first attached to the right side of the transverse colon and 

 subsequently to the left side, the intermediate space being filled 

 up later. The two earlier stages are represented in lower 

 mammals ; in Trichosurus the omentum is attached to the colon 

 only on the extreme right of the transverse bend, and in 

 Orycteropus and Hyrax the attachment is double, to the early 

 part of the colon and to a more distal region — the intervening- 

 tract being free of the omentum. 



(13) The view, deducible from previous investigations, that 

 four stages of advancing complexity are shown in the Mammalian 

 gut, is strengthened by fresh facts ; the Lemurs are shown to be 

 the only group in which all but one of these four stages occur. 



4. The Armour o£ the Extinct Reptiles of the Grenus 

 Pareiasaurus. By H. Gr. Seeley, F.R.S., F.Z.S., 

 King's College, London, 



[Eeceived April 29, 1908.] 

 (Text-figures 125-129.) 



In " Fui'ther Observations on Pareiascmr^ts" Phil. Trans. B. 

 Royal Society, 1892, 1 gave a short account of the dermal armour, 

 pp. 345-6. It is limited to the dorsal region, and is figured in 

 plate 17, and indicated by the letters ds in the description of the 

 plate, p. 368. The scutes are only known in this example of 

 Pareiasaurus baini, extracted from the rock by myself. They 

 were originally covered with matrix. Their existence was not 

 suspected, and it is possible that the more anterior scutes may 

 have been partly lost in removing the intractable rock ; and those 

 seen in the British Museum specimen were pi-eserved b}^ great 

 skill in chiselling. The ossifications are flat and inconspicuous, 

 except where the lateral plates overhang the neural spines. 



In the small figure of the skeleton given in the ' >Story of the 

 Earth,' 1895, text-fig. 18, p. 126, the scutes were made more evident 

 by dark outlines. Each scute is about 2 inches wide by 1| inch 

 long. There is a median row extending down the back, which as 

 preserved now rests upon the summits of the neural spines of the 

 dorsal vertebra and the interspaces between them. There are 

 also two lateral rows, one of which flanks each side of the median 

 row. These are arranged sj'mmetrically in jjairs, and extend 

 transversely outward from their contact with the median row, 

 but alternate with them by being placed at the junction between 

 each two jnedian scutes. The lateral scutes in Pareiasaurus baini 

 are not flat but convexly curved as they extend outward, giving 

 some support to the idea that this armour formed an elevated 

 ridge on the back. In the present condition of the specimen 

 this armour is only seen on seven consecutive later dorsal vertebra? 

 and one or two earlier dorsals ; and there is no evidence that 

 it was present over more than twelve vertebra?. 



