WEALDEN FORMATIONS. 9 



wanting the lower jaw, of a species {Crocodilus palustris ?) which is frequently found 

 inhabiting the larger ponds. It differs from the Cr. biporcatus of the Ganges in having 

 shorter maxillary and premaxillary bones in proportion to its length, and in having much 

 less developed prefrontal ridges ; the palatal suture between the maxillary and pre- 

 maxillary bones is transverse, not curved. The anterior extremities of the palatine bones 

 are narrower and more pointed. The number of alveoli is — premaxillary 5 — 5, maxillary 

 14-14." 



The doubt indicated (?) arose from the inadequate characterisation by Lesson, of the 

 species described by him in the 'Zoologie' of the ' Voyage aux Indes Orientales de Belanger;' 

 but there is no reference of the specimen, No. 752, to the Crocodilus rhombifer, as is 

 affirmed by the author of the " Synopsis of the Species of Recent Crocodiles," •' Trans. 

 Zool. Soc.,' vol. vi, p. 140. I did not regard my doubt as justifying the sinking of Lesson's 

 "palustris" into a synonym, and of imposing a new specific, much less generic name. 

 But the osteological character of the palatal region of the skull, pointed out in my 

 * Catalogue,' appears to be the chief of those relied upon by the author of that ' Synopsis ' 

 for his genus Bombifrons, of which the first character is : — " The premaxillary suture 

 straight, or rather convex forwards" (loc. cit., p. 139). The other characters are not of 

 specific value. 



The sutures of the premaxillary bones, I may remark, are of three kinds ; one is 

 medial and unites the pair ; it is the " interpremaxillary suture :" the second is lateral, 

 uniting the outer or dental plate of the premaxillary with that of the maxillary ; it is the 

 " premaxillo-maxillary suture :" the third is transverse, more or less, and unites the 

 palatal plate of the premaxillary with that of the maxillary ; it is the " premaxillo- 

 maxillary palatal suture." Its modifications, added to other differences, when determined 

 to be constant, may aid in differentiating the species of Crocodilus proper, of Alligator, 

 and of Gavialis) 



The convenience of these three genera of Proccelian Crocodilia, although they agree 

 in palatonarial and vertebral characters, will probably ensure their retention ; but 

 Tomistoma, Oopholis, Halcrosia, Palaosuchus, Rhynchosuchus, Ramphostoma, Mecistops, 

 Bombifrons, Palinia, Molinia, Caiman, Jacare, &c, into which they have been subdivided, 

 exemplify the evil of " encumbering the science with a multitude of names " (loc. cit., 



1 Prof. Marsh, in his 'Introduction and Succession of Vertebrate Life in America,' 8vo, 1877, 

 writes (p. 21) : 



"The beds of the Rocky-Mountain Wealden have just furnished us with a genuine "missing link," a 

 Saurian (Diplosaurus) with essentially the skull and teeth of a modern Crocodile, and the vertebrae of its 

 predecessor from the Trias." 



When the cranial characters of this Crocodilian are made known it will be of moment to compare the 

 temporal apertures on the upper surface and the palato-narial apertures on the under surface of the skull. 

 When the dental characters of the same fossil are described and figured we may be able to determine 

 whether they are those of the broad-faced proccelian Crocodiles and Alligators or those of Goniopholis. 



9 



