1886.] ON THE COLUMELLA OF ICHTHYOSAURUS. 405 



10. Note on the Presence of a Columella (Epipterygoid) in 

 the Skull of Ichthyosaurus. By A. Smith Woodward^ 

 F.G.S., of the British Museum (Natural History). 

 (Communicated by Professor Flower^ LL.D., P.R.S., 

 President.) 



[Received June 3, 1886.] 



In the skulls of fossil Reptiles and Amphibia it so rarely happens 

 that the bones on the inner side of the temporal fossa, and those 

 between tbe orbits, are well exposed to view, that even in some of 

 the most familiar genera very little has yet been ascertained regarding 

 the special characters of any of these ossifications. In so conspicuous 

 a form as Ichthyosaurus, for example, there appears to be no published 

 reference to these structures beyond the brief statements of Profs. 

 Huxley, Cope, and Sir Richard Owen, and even these do not afford 

 any very definite information. Prof. Huxley determined ^ the 

 presence* of a distinct pro-otic, and the doubtful absence of ali- and 

 orbito-sphenoids ; Prof. Cope gives ^ a diagrammatic outline of the 

 "columella"; while Sir Richard Owen appears to have been less 

 successful in his researches, having met witii nothing but unsatisfac- 

 tory indications of small " alisphenoids " (? pro-olics), and especially 

 remarking that there is " no trace or sign of the Lacertian columellar 



b)) 3 

 one 



In making the latter statement, the distinguished palaeontologist 

 just mentioned evidently overlooked Prof. Cope's previous researches 

 upon the osteology of the Ichthyosaurian skull ; and having lately 

 discovered that there is no foundation for the assertion in the British 

 Museum specimens, that formed the basis of Sir Richard Owen's 

 monograph, I venture to offer a few remarks upon the subject, by 

 way of pointing out the mistake. A detailed description of the 

 interesting bone in question may also be acceptable, since Prof. 

 Cope's materials appear to have been less complete and satisfactory 

 than those now afforded by the fossils from the English Jurassic. 



The first specimen of interest in this connection is a small slab of 

 Lias from Lyme Regis, exhibiting a number of dislocated cranial 

 bones, which Mr. William Davies long ago recognized as belonging 

 to Ichthyosaurus, but which do not appear, hitherto, to have been 

 submitted to so careful a study as their admirable state of preserva- 

 tion renders desirable. In the middle of the fossil, the basioccipital, 

 basisphenoid, and presphenoid are arranged in irregular series, with 

 their upper aspect exposed ; in front are the remains of the supra- 

 occipital and parietals ; and on either side are scattered a number of 



1 T. H. Huxley, 'Anatomy of Vertebrated Animals,' 1871, p. 211. 



2 E. D. Cope, " On the Cranium of the Ichthyopterygia," Proc. Amer. Assoc. 

 Adv. Sci. vol. xix. (1870), pp 200-203. (For this reference I am indebted to 

 the kindness of Mr. J. W. Hulke, F.R.S.) _ 



^ R. Owen, " Fossil Reptilia of the Liassic Formations.— III. (Mon. Pal. 

 See. 1881), p. 96; also, 'History of British Fossil Reptiles,' vol. iii. (1884), 

 p. 54. 



