18 ABNORMAL CONDITIONS OF THE AXIS. 



b. Schizocotis. 



Syn. Synkephalus asymmetros, Forster. 

 Janiceps, Geoff. 

 Janus- Bildung. 



88. A female Human foetus with posterior dichotomy extending 



into the base of the skull, probably as far forward as the 

 posterior part of the basisphenoid. There is a pair of 

 well-formed external ears behind fused together below, 

 with a single meatus between them. A small circular fossa 

 above these, with a depression in its centre from which a 

 minute tuft of hair is growing, probably represents a 

 rudimentary Cyclops-eye. Mus. Brit. 



89. A similar female Human foetus with the dichotomous condi- 



tion extending a little further forwards, so that a trans- 

 verse fissure corresponds to the position of a Cyclops-eye. 

 Brought from the East Indies in 1805. 



Presented by Sir E. Home, Bart., 1807. 



C. Antero-posterior Dichotomy. 

 Syn. Hemipagus, Geoff. 



Anterior and posterior dichotomy often coexist in the same 

 embryo. In animals there can be no doubt that this condition 

 is distinct from Homologous union', when it is extreme, how- 

 ever, as in No. 94, a human foetus, it is impossible to deter- 

 mine to which Subclass the phenomenon should be referred*. 



90. A foetal Kitten with complete dichotomy of the trunk, and 



a slightly double condition of the tongue and mandible. 



Hunterian. 



91. A similar foetal Kitten with more considerable dichotomy 



of the mandible and tongue, accompanied by cleft palate. 



92. A similar Kitten with the median anterior limbs fused as 



far as the carpus. 



93. A foetal Pig with posterior dichotomy (Schizorhachis) com- 



bined with anterior dichotomy of the lower jaw and 

 tongue. There is a considerable cleft in the palate con- 

 nected with the median rami of the jaw by a fold of 

 mucous membrane. (No. 52 exhibits a similar condition.) 



Hunterian. 

 * See Introduction. 



