HYPEROODOX. 83 



10. Teeth, rudimentary, projecting through gum from 



mandible, calcified and with acute points. 



11. Hard palate, mucous membrane of, rough, with numerous 



short, blunt papillae. 



12. Tympano-periotic bones, pair of. Length of Tympanic 



2^ inches, greatest breadth li inch, height 1^ inch. 

 Outer surface convex, divided hy an oblique groove 

 into two bulgings; from the groove to the anterior 

 border is 1-^ inch, to the posterior border 1 inch; the 

 lip-like process ascends for | inch from the upper 

 border of the posterior bulging, and is prolonged 

 down the outer surface. The inner surface is striated, 

 and divided into a thick posterior part j- inch high, 

 and an anterior longer part only ^ inch high. The 

 inferior aspect is 1| inch broad, and may be called 

 a surface ; posteriorly it presents a distinct outer lobe, 

 but the inner is a rudimentary tubercle ; a shallow 

 groove separates them, in which is a narrow ridge, 

 which extends to the anterior end of this surface ; 

 the cavity has a wide opening close to the Eustachian 

 end of the inferior surface Corresponding characters 

 exist in the tympanies of the other crania of Hyper- 

 oodon. See figure of inferior surface below. Periotic, 

 length 2 J inches, breadth Ih inch. 

 SeiDtember 1888. 



Donor — Capt. Phillips, " Nova Zembla," Dundee. 



13. Tympano-periotic bones, imperfect. 



Shetland, 1872. 



14. Tympano-periotic bones from No. 2. Tympanic, length 



2{ inches, breadth 1^ inch, height 1^ inch. Periotic, 

 length 2^ inches. 

 Dunbar, 1885. 



