4 FOSSIL REPTILIA OP THE 



structure of the vertebrae, the Crocodilian of the Purbeck limestone, like others of the 

 Mesozoic epoch, was probably more marine than existing Crocodilians. The caudal 

 vertebrae were provided with long, narrow, unanchylosed chevron bones. 



The portion of the mandible preserved in the Purbeck slab belongs to that part of 

 the left ramus included between the articular extremity, which is broken off, and the 

 hind commencement of the dental series, of which two teeth (PI. I, fig. 7) remain. This 

 portion of jaw measures 1 foot 6 inches in length, and 5 inches in greatest depth. In 

 these proportions, and the curve of the lower margin, it deviates from the Oolitic 

 Teleosaurs and Steneosaurs, and resembles the modern Crocodiles ; and although not 

 quite equalling these in the robust proportions of the jaw, yet it much exceeds in this 

 respect the Crocodilians with more slender teeth. 



Portions of the skeleton of a Goniopholis, kindly submitted to my examination by 

 G. B. Holmes, Esq., of Horsham, by whom it was discovered in a Wealden stratum at 

 Cuckfield, Sussex, include the fore-part of the premaxillaries (PI. I, figs. 1 arid 2). 

 This shows a semicircular anterior contour, and a single subcircular nostril (fig. 2 w), 

 placed rather nearer the termination of the muzzle than in existing Crocodiles ; but yet 

 above ; not terminal, as in Teleosaurus, nor subterminal, as in Steneosaurus. There is 

 not enough of the bone preserved to show whether there was a constriction of the upper 

 jaw behind the nostril, as in the Gavial. The incisive foramen is not immediately beneath 

 the nostril, as in the modern and Tertiary Crocodiles. The outer surface of the 

 premaxillaries is convex, rather irregular, with vascular foramina and wrinkled impres- 

 sions. The margins of the symphysis (*) are a little produced. There are four alveoli 

 in each premaxillary, as far as the bone is preserved ; they are proportionately larger, 

 more numerous, and closer together than in the corresponding part of the Strepto- 

 spondylus or Steneosaurus brevirostris} The first and smallest socket is in contact with 

 the second, which is the largest ; the intervals increase beyond this socket (PI. I, fig. 1). 

 The palatal surface shows a pair of large and deep approximate fossae, and a second pair 

 of smaller fossae, apparently for lodging the crowns of the anterior teeth of the lower jaw. 



The subject of fig. 5, PI. I, is from the Purbeck stone, and of a somewhat larger 

 individual than the Cuckfield specimen. 



In a mandibular fragment from Cuckfield (PI. I, fig. 8) the cylindrical fang of a 

 well-preserved tooth is invested by smooth cement ; the coronal ridges begin at the 

 basal line of the enamel, and proceed nearly parallel to the apex of the cone. In a tooth 

 with a crown one inch long and half an inch across the base four ridges are included in a 

 space of one line's breadth ; a few of the ridges are interrupted to preserve the parallelism 

 of the rest. Towards the apex a number of shorter and finer ridges are present on each 

 side of the two chief ridges, to which they obliquely converge. At the extreme apex of 

 an unworn tooth the ordinary ridges terminate in fine, slightly wavy lines, forming a 

 subreticulate surface. 



1 ' Ossem. Fossiles,' 4to, t. v, pt. 2, pi. x, fig. 6. 



