SKULL AND OTHEE BONES OF LOXOMMA ALLMANNI. 223 



equally suggestive of the actual perforation of the corresponding 

 part in Lepidosteus, and in the old Crocodile of the Nile, for the 

 reception of a tooth of the mandible when the mouth is closed. 



The apertures in each parietal bone, so large in the Crocodilia, 

 are not present in Loxomma; but the u parietal" foramen, which 

 exists, is a character common to it and the other Labyrintho- 

 donts, to Ichthyopterygia, Sauropterygia, and Anomodontia, but 

 does not belong to Fishes. 



The temporal fossae are, in Loxomma as in Crocodiles, Alliga- 

 tors, Tortoises, and Batrachia, placed on the sides of the top of 

 the skull, and are not arched over by bony plates as in the Pro- 

 topteri and Ganocephala. 



The articulations of the mandible with the skull resemble the 

 corresponding parts of the higher Reptiles rather than those of 

 Fishes. 



The large size and great importance of the superior maxillary 

 bones as compared with the premaxillaries is a decided reptilian 

 and not at all an ichthyic character. 



The skull of Loxomma has two pairs of bones that are wanting 

 in Fishes and in the Crocodilia, namely, the postorbital and the 

 supratemporal ; these contribute much to enhance both the 

 length and the breadth of the cranium ; they are present, how- 

 ever, in the Ganocephalous Dendrerpeton and Archegosaurus, in 

 the Labyrinthodontia, and in the Ichthyopterygia ; but the ge- 

 neral ossification of the skull is much further advanced and con- 

 solidated in Loxomma than in these other animals, whilst in 

 Archegosaurus, at least, it is very incomplete, having "been 

 chiefly active at the surface" (Owen, Pala)ont., p. 195). 



Besides the above two pairs of bones there is in Loxomma, as 

 in Archegosaurus, another pair, to which attention was called 

 above in the description of the bones, and which lies between 

 the parietals in front and the occipital vertebra behind. This 

 pair is called by Owen, Huxley, and Yon Meyer "supraocci- 

 pital." 



Now in Loxomma, at least, though not in Archegosaurus, on 

 account of incomplete ossification, the occipital vertebra is 

 formed by the basi- and ex-occipitals and a fourth piece of 



