MONSTROSITIES. 



409 



ities which, though united, have one being more or less complete — being 

 reduced in fact to a limb, jaw, or other fragment of a body implantsed or 

 subsisting on an individual which is fully developed. iThese are included 

 in Gurlt's second Class. 



In the autositaric order we have the Eusomphalian and Monophalian 

 monstrosities : these have the common character of two heads and four 

 pairs of limbs ; the first have, however, a distinct umbilical cord to each 

 of the united foetuses ; while in the other — the Monophalian — there is 

 only a single umbilical cord and umbilicus. 



The Eusomphalian monstrosity consists, then, of two pretty equally de- 

 veloped foetuses, each with its own umbilical cord, the two being usually 

 joined together by some soft part at any region of the body ; so that they 

 may be separated by a surgical operation without the existence of either 

 being compromised. This is included in the third Order of Gurlt's sec- 

 ond Class. 



With the Monomphalian monstrosity, on the contrary, there being only 

 one umbilicus and one cord, the foetuses are joined at the ventral surface, 

 and have usually several organs in common — notably the liver, to which 

 the umbilical vein passes (Fig. 96). 



The Sy?tcephalia7i monstrosities have two bodies either completely sep- 

 arated, or only divided above the umbilicus, and surmounted by a more 

 or less incomplete double head : the two heads being fused, as it were, 

 into one {Dicephalus heterocephalus of Gurlt — Fig. 97). 



The Monocephalian monstrosities, as the name implies, differ from the 

 last in having only one head but a double body, the separation of the two 

 usually taking place below the umbilicus (Fig. 98). 



The Sysoinian monstrosities (Fig. 99) have two 

 heads on apparently a single body though a closer 

 investigation will prove that the unicity is merely 

 superficial, and that at least some parts are double. 

 Gurlt describes a full-grown Sysomian lamb he ex- 

 amined, and which had, apparently, a single body 

 and only four feet, but two necks, two heads, and 

 two tails, and the skin normally covered with wool. 

 The trunk, though somewhat small, gave no indica- 

 tion of its duplicity. It had, nevertheless, two ver- 

 tebral columns, the inner ribs attached to each 

 being shortened and fused together, while the ex- 

 ternal ones were attached in the usual way to the 

 single sternum. The viscera were generally double, 

 though they were confounded at certain points. A 

 single heart sufficed for two pairs of lungs, one 

 pair of which, however, were only rudimentary. 

 The two livers were combined into one, and in some 

 parts the intestines merged into a single tube, 

 again to become double, and finally to terminate in 

 one rectum. 



The Monosomian monstrosities have, in reality, 

 only a single body, the duplicity generally com- 

 mencing towards the neck, In the cervical region, 

 not unfrequently at the atlas, and sometimes as far as the facial region 

 (Fig. 100). 



Among the double parasitic monstrosities, we may mention Saint-Hi- 



Fig. 98. 



Monocephalian Mon- 

 strosity : Corttio-Me- 

 lodidymi (Gurlt). 



