172 MR. H, G. SEELET ON OSSEOUS RESEMBLANCES 



Dinosaur Scelidosaurus. The palate, thougli flat and closed, as in 

 Crocodiles, would seem rather to be constructed after the plan of 

 ChamcBleon and of those Emydian Chelonians from which that 

 plan is modified ; for the pterygoids, according to Dr. Giinther, 

 entirely divide the palatine bones extending between them to 

 meet the vomera, with which they form the middle of the osseous 

 palate ; in Crocodile they only advance a little way between the 

 palatines, and the vomer does not come into the palate. 



The parietals diverge behind as in Lizards ; and the diverging 

 processes are overlapped by the squamosal. Yet parietal, frontal, 

 nasal, and premaxillary are all double ; and between the parietal 

 and frontal is a foramen parietale. 



The vertebral column (since the vertebrae are biconcave, devoid 

 of transverse processes in the back, with oblique neural spines 

 and, in the caudal region, with small chevron bones) has little in 

 common with the Crocodile's, Still the articulation of the centrum 

 is vertical ; the first three vertebrae in the neck have no ribs ; the 

 fourth has a double head, but rather after the plan of Pliosaurns 

 than oiCrocodilus. The dorsal ribs have epipleura which in the 

 early vertebrae are cartilaginous as in Crocodiles, and the middle 

 ones ossified as in birds, but remaining unanchylosed as Dr. 

 Giinther found them to be in the mature egg of the Pheasant. 

 The sternal and haemal ribs are very unlike the Crocodile's. The 

 caudal vertebrae divide into anterior and posterior parts, as in 

 Lizards. 



The sternum, episternum, and clavicles are after the plan of 

 Lizards'. The perforated coracoid more nearly resembles that of 

 the Chameleon, while the flattened ossified portion of the scapula, 

 which has a slight spine, is in the main Crocodilian. 



The pelvis is about intermediate between Ghamceleon and Tes- 

 tudo, and in no respect Crocodilian. The limbs are essentially 

 Lacertian. 



§ 6. The CJielonian Characters of Crocodiles. 



In Chelonians the quadrate bone is wedged into the skull much 

 as in Crocodiles, though it is usually vertical, with a tendency to 

 incline forward rather than backward. It is similarly united to 

 the malar by a squamous quadrato-jugal, though in the Testudine 

 family, owing to enormous excavation of the quadrate and squa- 

 mosal bones, the squamosal has a tendency to retreat up the side 

 of the quadrate after the plan of Lizards. The malar bone in 



