Harris Hawthorne Wilder 



407 



the remaining cases cited under this subdivision will be those which show 

 the opposite principle, that of duplication below with a single head and body. 

 Here also the cases will be arranged in a decreasing series, ending as in if) 

 with a single body showing but a few traces of the two components.] 



g. Two nearly complete components, joined front to front over more or less 

 of the trunk region, hut with a single necJc and with the heads more or less 

 completely fused into a single compound mass. The half-faces of the two 

 components meet in the plane of union and form single faces of a varying 

 degree of completeness, placed laterally tcith respect to the components. 

 Janiceps. 



These are the so-called Janus-headed monsters, two varying degrees of 

 which are represented in Fig. 5. At first sight these monsters seem at vari- 

 ance with the general plan of diplopagi, since what appears to be the face 



Fig. 5. Lateral view of two cephalothoracopacri (Janus monsters), showing different 

 degrees of separation. The face which is towards the observer is duplicated in these mon- 

 sters by another one on the opposite side, and thus from the dorsal aspect of either com- 

 ponent there appear two profiles looking- in opposite directions. Each lateral face is in 

 reality composed of halves contributed by the two components. 



components are placed laterally with respect to the trunks; but if the plane 

 dividing these latter be conceived as passing through the faces also, it be- 

 comes evident that what seems a single face is made, in each case, of the 

 right half of one component and the left half of the other, and that thus the 

 two components are as completely bilateral as in other cases. The case is 

 identical with that of the laterally placed genitalia in ischiopagi. 



h. One head and one trunk (and consequently a single individual), but 

 tvith double ijelvic organs and two pairs of legs (dipygus). 



Type: Wells' case, Mrs. B., born May 12th, 1868, lives in Birmingham, Ala. 

 Normal down to the third lumbar vertebra, where the duplication begins, 

 resulting in a fused double pelvis, and two pairs of legs; of these latter the 

 inner ones, although of normal shape, are somewhat reduced in size, either 

 from lack of room for development or in part from disuse, since the outer 



