148 Dr. 0. W. Aiulrewa on 



The precise systematic position of this chelonian is not 

 certain, l)ut it must belong cither to the Amphiehelydia or to 

 the Pleurodira. It may he referred to the genus Trachydcr- 

 moche/ys, founded by Seelcy * for the reception of some 

 scutes from the Cambridge Greensand, possessing a nearly 

 identical type of sculpture, their S[)ecitic name being T. p/ily- 

 ct(enns ; the species has never been properly described and 

 tigured, and Lydekker f has suggested that these scutes may 

 actually belong to species of Rhinochelys. This, however, is 

 by no means certain, and I therefore prefer to enii)loy the 

 name Truc/iydermochelys given to the sculptured scutes. In 

 the Cambridge Greensand species the sculpture is consider- 

 ably finer than in the present specimen, which, moreover, is 

 from a different horizon : for these reasons I propose to refer 

 it to a new species, for which the name Trachy dernwchel ys 

 rutteri is proposed. 



A Chelonian shell from the Upper Greensand of the Isle 

 of Wight was described by Owen (quoted by C. Parkinson) 

 in the Quart. Jovirn. Geol. Soc. vol. xxxvii. 1881, p. 370, 

 and was made the type of a new geuus and species under the 

 name Plastremi/s lata. This specimen is R. 48 of the British 

 ^Museum collection. The only character mentioned by Owen 

 is the al)sence of the mesoplastral elements, and this is an 

 error; the ])romised further description never appeared. In 

 1889, Lydekker (Catal. Foss. Rept. Brit. Mus. pt. iii. p. 195) 

 referred this specimen to his genus H>//(eochehjs, rc{)cating 

 the statement that mesoplastra are absent. Re-examination 

 of the shell, however, shows that not only were these elements 

 present but that they were large, and that a sculpture similar 

 to that of Trachodermoc/ie/ys, though not so strongly marked, 

 was present in the region of the bridge, the rest of the shell 

 so far as known being smooth. It seems almost certain thaf 

 this specimen represents another sj)ecies of Truclit/der- 

 mochely<f the name of which would be Trachydcnnuchelys 

 lata, Owen, sp. 



The second specimen here described is part of the carapace 

 of a tortoise from the Barton Clay at the foot of Iligheliir, 

 near Christchurch, Hants. It is preserved in the Museum 

 of Practical Geology, Jermyn Street (No. 20497). The parts 

 of the shell present arc : the right half of the nnehal bone, 

 the five anterior marginals, the live anterior ncurals, the four 

 anterior costals, and part of the fifth on the right side, while 



* ' Index to A ves etc. in tho Canibridp^o Mnscnni,' pp. xix Sc 33 (1809). 

 These spociniuns h.ivo nrver been luojifilv lij^uivd or Ji'.-;cribed. 

 t Lydekker, Catal. Foss. Kept. IJrit. Mus. j>t. .'i. p. 182. 



