222 Revieivs — Dr. A ndreivs — Marine Reptiles, Oxford Clay. 



M. Iceve, M. Leedsi, and 31. cuUridens, are, however, entirely new and 

 have not been previously described. The seventh, M. durohriveme, 

 Avas known as long ago as 1890, but was then called SucJiodiis by 

 Lydekker. It has now, and without a doubt correctly, been assigned 

 to Metriorhynchus. An excellent and most useful figure (No. 73) 

 enables the principal points of difference in the skulls of these seven 

 species to be obtained at a glance, though it is doubtful whether both 

 this figure and plate xi are not liable to convey a somewhat false 

 impression as to the nature of the sculpture of the frontal bones of 

 31. cuUridens. The species is based on R. 3804, an example in which 

 these bones, when found, were covered by hard concretionary matrix, 

 such as is still visible on the palatal surface, and the process of 

 freeing the bones from this matrix has seldom been executed without 

 the removal of parts of the surface of the actual bone along with it. 

 Such parts, however, as are still uninjured suggest that the sculpture 

 must have closely resembled that of 31. hrachyrhynchus. On the other 

 hand, a view of the uncrushed posterior aspect of this skull would 

 probably have given a better idea of the form of this region than that 

 of 31. durolrivense on plate xiii, which has admittedly suffered some 

 compression. 



One result of Dr. Andrews' examination of this genus is that he 

 entirely discards as an unreliable criterion the measurement across 

 the prefrontals, hitherto employed as one of the standard dimensions 

 for recognizing the various species. 



No mention is made of ventral ribs in connexion with 3Ietrio- 

 rhynchus. These, though scarce, are not unknown, but perhaps are 

 not contained in the Museum collections. It would have been 

 interesting to know whether Dr. Andrews would have regarded 

 them as another characteristic acquired by the Metriorhynchidae, in 

 accordance with their more aquatic habits, which led them to discard 

 the dermal armour with which the amphibious Teleosaurs were 

 protected. 



The comparison of the Metriorhynchidce with the slightly later 

 Geosauridte is interesting and useful, but we hardly think that it 

 called for the insertion in a Catalogue of English Oxford Clay Marine 

 Keptilia of a whole-page illustration of a specimen of Geosaurus, 

 a genus which must already be familiar to all students of vertebrate 

 palseontology from Continental Avorks. Skeletons of Geosauridse, 

 in the condition in which the Metriorhynchidae have been recovered 

 from the Oxford Clay, are unknown on the Continent, and even if no 

 skeleton of 3Ietriorhynchus was considered worthy of the honourable 

 position of the frontispiece, surely some other, for example the 

 typically Oxfordian Peloneustes, might well have had this plate allotted 

 to it. It may argue for a greater degree of cosmopolitanism on the 

 part of English scientists, but it is well-nigh inconceivable that any 

 continental scientific institution would have figured in a similar 

 position a skeleton from England, however much they might have 

 been alive to its importance for comparative study. In any case, in 

 the present instance the result can hardly be said to justify the 

 decision which prompted its insertion. Apart from this the illustra- 

 tions leave little to be desired. Thev are executed with all her 



