54 ABNORMAL CONDITIONS OF THE AXIS. 



b. Nanocephalus. 



210. The skull of a foetal Lamb with deficiency of the entire axis 



in front of the basisphenoid region. The mandible and 

 all the facial structures,, except a shallow orbit, are absent. 

 The squamosal bones are united beneath the skull. The 

 bullse of the ears are not fused in this preparation. 



Presented by C. B. Rose, Esq., 1869. 



211. A foetal Puppy with a nanocephalous skull. There is a 



very imperfect Cyclops-eye, a soft imperforate frontal 

 proboscis, and a similar structure representing the max- 

 illae. The pharynx opens through the aural tract. The 

 roof of the skull has been removed to show its base from 

 within. The axis terminates in the basisphenoid region, 

 immediately in front of the foramen magnum. All the 

 bones of the skull except those of the ear- capsule are very 

 small ; these are of their normal magnitude, and occupy 

 a very large part of the base of the skull. Mus. Brit. 



212. A nanocephalous foetal Puppy with no eye or orbit j it is 



otherwise similar to the last. Hunterian. 



213. A similar foetal Hare, but without any maxillary proboscis. 



214. A similar nanocephalous foetal Kitten, but without any pro- 



boscis. There is a caeca! foramen representing the orbit. 

 The tympanic bullse are united. The single meatus ex- 

 ternus has been laid open to show the tympana ; beneath 

 these is a passage, marked by a bristle, leading into the 

 pharynx. The thoracic cavity has been opened and the 

 thymus removed to show the normal condition of the 

 heart and lungs. Hunterian. 



215. A microcephalous foetal Pig with fusion of the tympanic 



cavities. A small bifid tubercle on the face is the only 

 remnant of the united and atrophied eyes. There are no 

 other facial organs except a pair of external ears that are 

 united by their bases. The neck and thorax have been 

 laid open to show the perfect condition of the hyoid arch, 

 larynx, trachea, and lungs. The calvarium has been re- 

 moved to show the base of the skull. Hunterian. 



216. The nanocephalous skull of a similar foetal Pig. The squa- 



mosal bones are fused together and form a square pro- 

 jecting plate above the united tympanic bullse. The 

 frontal bones are very defective. The basioccipital is the 



