MALI-'ORM A'i'lONS. 



y9 



Si/ninclusiiionopus. An i.-idividual liavintj fuscil legs and unly 

 one fiiot. 



Syiuiu-liisal>iis. A monster having fused legs and no feet. 



Sy)iorcIiisiu. A nialfomicd animal in wliieh llie testicles are 

 fused. 



Arrested development may lie evidenced 1)\- the nonappear- 

 ance of the lumen in any of the natural hrillow organs, (atresia). 

 The mouth is formed by an ingrowth of tlie ectoderm and the 

 buccal cavity extends inward until it meets the anteri(jr elonga- 

 tion of the embryonic gut. iJater the partition separating the 

 Iniccal cavity^ and the cavity of the embr\'onic gut is ahsorljed 



Fii^. 71, — A cunditiuu ul Sinlii)ediu In a liuy, 



and thu.s the cavities become continuous, b'ailure of the exten- 

 sion of the mouth cavity and its fusinn with the embryonic gut 

 constitutes the condition. Atresia Oris. 



.ItrcSKi iridis. A defect in the eye due to the absence of an 

 Opening (pupil). 



Atresia ociili. a malformation in which there is no cipeni.ng 

 between the eyelids. 



Atresia anus is a condition in which there is an imperforate 

 anus, that is, there has been failure of union and fusion of the 

 anal ingniwth and the rectal outgrowth. .Atresia anus is of 

 rather frequent occurrence and usually the defect is easily re- 

 lieved. 



Atresia urctlini. lni])erforatiou of tiie uretnra. 



