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PROP. H. G. SEE LEY ON HETEROSUCHTJS VALDENSIS 



18. On Heterostjchtjs valdensis, Seeley, a Proccelian Crocodile 

 from the Hastings Sand of Hastings. By H. G. Seeley, 

 F.P.S., F.G.S., Professor of Geography in King's College, 

 London. (Read March 9, 1887.) 



[Plate XII.] 



The specimen in the British Museum, numbered 36555, came there 

 in the second Mantellian collection, which was acquired after Dr. 

 Mantell's death. It is part of a thin ironstone nodale, 10 centim. 

 long and 6 centim. wide, from the Hastings Sand of Hastings, mani- 

 festly water-worn, but containing vertebrae which have not hitherto 

 been determined. The nodule (PL XII. fig. 7) displays the remains of 

 f ully a dozen vertebrae, which extend round the nodule in parts of more 

 than one coil, so arranged as to expose the ventral surface or bodies 

 of the vertebras, towards the external margin of the concretion. 

 These vertebrae indicate a proccelian Crocodile of small size ; and 

 although the remains are so imperfect, I refer them to a new genus, 

 since their forms are different from those of any Purbeck Crocodiles 

 or other described Crocodilia. 



The nodule displays some other vertebrate remains which may 

 possibly belong to another kind of animal. Thus in a transverse 

 fracture the outlines may be traced of two long ovals which extend 

 in the same axis, and may represent the superior aspect of the 

 parietal region of a small skull, in which each temporal fossa is 13 or 

 14 millim. wide and 7 millim. long. The external surface appears to 

 show a very fine punctate ornament, not unlike that seen in some 

 small Purbeck Crocodiles ; and what might be the quadrate bone is 

 seen to extend in an outward direction as it is prolonged distally. 

 No proccelian Crocodile has the temporal vacuities elongated in this 

 way ; but from the imperfect preservation and small size I am 

 doubtful whether the skull should be referred to the same animal as 

 the vertebrae, on the hypothesis that it is to be included in the 

 Proccelia. 



On the worn external surface of the nodule, somewhat below the 

 remains of the sacrum, are some obscure outlines of bones, which 

 can only be followed with difficulty, but which may be pubis and 

 ischium ; and in the position in which the acetabulum might exist, 

 there is a well-defined hemispherical pit. These bones are much 

 smaller than would have been expected ; but their proximity to the 

 sacral vertebra makes it important to remark that the acetabulum 

 is that of a lacertilian, while the forms of the bones which combine 

 to form it are not crocodilian. In the possibility that all the 

 remains may be portions of one animal, this fossil would diverge 

 from existing Crocodiles in a direction of which no crocodilian has 

 hitherto given evidence. 



The vertebrae include one late cervical, eight dorsals, and two 

 which may be classed as sacral. These vertebrae are remarkable 



