86 SPECIMENS OF CETACEA. 



81. Eyeball, in the orbit, antero-posterior section with the 

 eyelids, the palpebral fissure, and the two grooves in 

 the lids ; the retractor muscle, two of the recti, and 

 the orbicularis are seen in the section, as well as the 

 lens, the vitreous body, the coats of the eyeball, and 

 the optic nerve. Goodsir Collection. 



32. Eyelids with palpebral fissures. In each lid is a groove 



parallel to the fissure, which apparently facilitates 

 the movement of the lids. The opposite surface of 

 the preparation shows in section the anterior segment 

 of the eyeball. Goodsir Collection. 



33. Ear. Integument of Hyperoodon from the auditory 



region, showing the minute orifice of the external 

 auditory meatus on the surface. Turner Collection, 



84<. Tympanum. Fibro-mucous membrane, pouch-like lining 

 of the tympanic cavity of Hyperoodon. Figure below. 



Turner Collection. 



35. Skin of Hyperoodon. A portion of the superficial thin 

 pigmented layer of cuticle has been reflected to show 

 the deeper layer attached to the cutis vera. 



Goodsir Collection. 



V. MESOPLODON. (Me.) 



Mesoplodon, Gervais, Ann. Sc. Nat., 1850. 



Skull with mesethmoid ossified in adult into a medio- 

 rostral bone. Beak long and narrow. No maxillary 

 crests ; nasals narrow, concave forwards, lodged 

 between the upper ends of premaxillse. Pair of 

 large teeth in mandible at some distance from the 

 tip. Sternum consists of four or five pieces. Skull 

 asymmetrical. 



