A CASE OF CYCLOPIA 209 



has already been noted, passed directly to the inferior surface 

 of the latter muscle. 



On the left side, the opening in the bony roof of the orbit was 

 continued posteriorly and the floor of the middle fossa of the 

 skull was removed to the level of the foramen ovale. It will 

 be here noted that the whole extent of the upper surface of the 

 left maxillary element is exposed, together with the maxillary 

 division of the fifth nerve and its overlying muscular band. Pos- 

 teriorly is seen a well marked deep fossa. The mandibular di- 

 vision of the fifth nerve divides into a number of branches which 

 pass into a thick .muscular mass which, as far as it can be judged 

 from its location, probably represents some part of the pterygoid 

 group. 



Posteriorly in the orbital fossa is seen the inferior portion of 

 the postero-median muscular band. Also at this level from the 

 region of the central fibrous mass two muscular bands pass lat- 

 erad to be inserted into the fibrous tissue on the anterior surface 

 of the bony wall of the maxillary element. At a lower level in 

 this region is seen a layer of muscle whose fibers have already 

 been noted as coursing laterad parallel to the anterior convex bor- 

 der of the crypt. It is seen to have a somewhat wide origin 

 in the mid-line below the central tendinous mass. As the fibers 

 pass outwards they converge and are inserted into the deep fascia 

 at the lateral margin of the orbital fossa. 



Two muscles, which from their relations represent the inferior 

 recti, pass almost directly downwards from the central tendon 

 to their insertions on the bulbus. The insertions of the rectus 

 superior and lateralis muscles are also indicated. 



In the mid-line in front, the roof of the orbit has been dissected 

 away to show the point of attachment of the proboscis and its 

 relation to the eye. 



The arrangement of the orbital contents throughout is very 

 similar to that obtaining in the cyclopian eyes dissected by Wilder 

 (28). As in his cases, the mesial recti muscles are absent owing 

 to the complete suppression of the area in which they normally 

 develop. The superior oblique muscle was not identified in 

 this case. 



