ON THE CKANIAL CHAKACTEKS OF A TELEOSATJR. 627 



44. Note on the Cranial Characters of a large Teleosaur from the 

 Whttbt Lias preserved in the Woodwardian Mttseum of the 

 University of Cambridge, indicating a new Species, Teleosatjrus 

 eucephaltjs. By Professor H. G. Seelet, F.R.S., F.G.S., &c. 

 (Eead June 23, 1880.) 



[Plate XXIV.] 



The Woodwardian Museiim of the University of Cambridge has 

 long contained the cerebral region of the skull of a large Teleosaur 

 from the Lias of Whitby, which differs in important characters from 

 the Teleosaurs hitherto described, and adds some interesting points 

 to our knowledge of the cranial characters in this extinct suborder 

 of animals. Attention was briefly drawn to the specimen at p. 121 

 of my ' Index to the Fossil Eemains of Eeptilia &c. in the Wood- 

 wardian Museum,' 1869. The skull has been transversely fractured 

 anteriorly, posterior to the suture between the parietal and frontal 

 bones, so that no part of the frontal region is preserved, and there- 

 fore no indication is given of the anterior expansion of the skull 

 beyond the long temporal fossae. The crest of the parietal bone 

 appears to have been more than usually wide and strong, but that, 

 too, is imperfectly preserved. The quadrate and squamosal bones 

 are broken away at the sides ; the base of the occipital region is 

 fractured, and the pterygoid bones are absent ; but the very imper- 

 fections of the specimen led to its being sawn through in the median 

 line, so as to display a vertical section of the brain-case. Care has 

 been taken to make the section so as to throw light on the lateral 

 modifications of the brain-case ; and I now venture to submit to 

 the Geological Society some account of the characters thus dis- 

 played. In existing Crocodiles the brain-case is relatively small, 

 owing to the shortness of the parietal region, and it is imperfectly 

 closed anteriorly ; here it is much longer and larger in proportion 

 and closed by bone in front. The thickness removed by cutting and 

 polishing the cerebral section makes the right half of the skull 

 about half or three quarters of a centimetre narrower than the left 

 half. 



On the left side (PI. XXIY. fig. 1) the extreme length of the frag- 

 ment, from the basioccipital articular surface to the anterior fracture, 

 is about 19 centimetres : the extreme depth of the specimen as pre- 

 served is about 12 or 13 centimetres ; the brain-cavity is narrow and 

 about 14 centimetres long, but on this side appears to have extended 

 anteriorly a little beyond the extremity of the bone. The termination 

 of the brain-cavity is 2 centimetres deep, and 8 millimetres in trans- 

 verse width, as seen on the anterior fracture, where the outer margin 

 is convex. The cranial ■ cavity is long, and has its superior and 

 inferior walls slightly diverging as they extend backward. At a 

 distance of 1| centimetre posterior to the anterior fracture the 



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