from the London Clay. 233 



At the upper part of its lateral margin adjoins the flattened 

 marginal plate, % of an inch wide. Between the nuchal arid 

 first costal rib there appear to have been three marginal plates, 

 none of which touch the first costal plate. 



The first costal plate appears to be an irregular pentagon, 

 about \\ inch long at the suture with the first neural plate, 

 nearly If inch long behind the nuchal plate ; behind the 

 marginal plates it again becomes narrow. Herein it is unlike 

 the recent marine Chelonia. 



The second costal plate, which is less than 1^ inch long at 

 the neural suture, widens at the marginal end to If inch. 

 The third and fourth costal plates measure at the neural suture 

 each 1-i^ inch, but spread a little towards the mai'ginal 

 ends. The fifth and sixth pairs are not so well preserved, but 

 similarly widen towards the margin, as does the seventh pair. 

 The eighth pair of costal plates is much longer from back to 

 front than the seventh, and, as in the type of G. harvicensis^ 

 supports the eighth and ninth pairs of costal ribs. Beyond 

 this point the carapace is not preserved. 



I anticipate that it will prove to be specifically distinct from 

 the species described, and that the hyosternal bone next no- 

 ticed may be referred to it. 



A nodule exhibiting the greater part of a right hyosternal 

 bone similar in size to that in the typical specimen of C. har- 

 vicensis. Its shortest measurement, from the deeply cupped 

 front to the hyposternal suture, is about 1-^ inch. At the free 

 marginal side the sharp rays are well seen ; they differ from 

 the type in being elevated above the bone on which they rest, 

 much as the rib is elevated in its passage along a costal plate. 



Scarcely any group of described vertebrates more urgently 

 demands a renewed critical study than the Tertiary Chelonia. 

 The case has yet to be made out which will justify the refer- 

 ence of any one of Prof. Owen's species to the genus Chelone, 

 while the majority are obviously Emydians, with very little 

 to even insinuate their affinity with the chelonian suborder, 

 some, like the so-called Chelone longicej^s (Owen), being va- 

 luable new types for comparative study. 



Glossochelys^ if the hyoid bones can be credited with such 

 an inference, may have had a voice like a trumpet, and have 

 served as an alarmist to the gentler inhabitants of the Spice 

 Islands of lat. 51° or 52°, whenever he gave tongue. 



