46 ABNORMAL CONDITIONS OF THE AXIS. 



174. A foetal Kitten with partial fusion of the eyes and a small 



frontal proboscis. Hunterian. 



175. A male Human foetus, about the seventh month of gesta- 



tion, with deficiency of the facial axis and a frontal pro- 

 boscis. The eyes are contained in a single median orbit 

 and fused as far as the corneas. The right external ear 

 and the thumb of the same side are very defective. 



Mus. Brit. 



] 76. The head of a Human foetus similarly affected. A trans- 

 verse vertical section has been made through the poste- 

 r i r P^ r t of the head to show the condition of the brain. 

 The section passes through the corpora quadrigemina, 

 the fourth ventricle, and the cerebellum. The corpus 

 callosum is absent, the fornix is rudimentary. The cor- 

 pora quadrigemina are very large, the cerebrum is small, 

 and entirely contained in the anterior portion of the skull. 

 The third ventricle, together with the lateral ventricles, 

 forms an enormously dilated cyst, occupying the whole 

 of* the back and upper part of the cranial cavity. 



Presented by C. H. Welch, Esq., 1868. 



177. The posterior part of the brain of the same foetus. 



Presented by C. H. Welch, Esq., 1868. 



178. A longitudinal vertical section of the head of a similar 



foetus. The cerebral lobes are very small, and exhibit an 

 unmistakable condition of arrest. The corpus callosum 

 is absent, and the fornix is rudimentary. The condition 

 of the ventricles as well as the rest of the brain is similar 

 to that seen in the last preparation. The cavity of the 

 proboscis extends back to the dura mater. 



b. Arhynchus. 



Syn. Cyclops Arhynchus, Gurlt. 



In the following preparations the frontal proboscis is absent, 

 indicating a still higher degree of anterior facial arrest. 



179. The head of a foetal Lamb with the eyes partially fused 

 together. The upper part of the skull has been removed 

 to show the small size of the basisphenoid, the persistence 

 of the trabeculae cranii, and the absence of the presphe- 

 noid and ethmoid bones. The optic foramina are fused 



/e-<t*m t&V 

 H 



