Harris Hawthorne Wilder 415 



of a median arm, and with a doubling of the pelvic organs in place of the 

 head. 



Ex. — Dos Santos. Bechlinger's case. 



B. III. — In this there is a complete duplication of the body below 

 the lumbar region, each half furnished with a normal pair of legs, 

 although there may be some lack of development in the inner legs in 

 the same way and for the same reason as in the case of the inner arms in 

 V and VI of series A. 



Ex.— Wells' case (Mrs. B.). 



Beyond B. Ill there seem to be no authentic cases with laterally 

 placed components, but the first stage of series C, although differing in 

 the geometrical relation of the components, might in other respects 

 stand as B. lY, in which, in addition to the doubling of pelvis and legs, 

 there is an incipient doubling of the head. 



Series C may thus be placed in the same row as B and may be desig- 

 nated as follows: 



C. — Separation at First from Below Upwards, Succeeded by One 

 FROM Above Downavards; Components Placed Face to Face. 



C. I. — From the umbilical region downwards two separate bodies, 

 chests united and each component less than a whole one; head partly 

 doubled, with tn'O occiputs, faces incomplete, with one median eye on 

 each lateral aspect, formed of equal contributions from each component. 

 An incomplete Janus monster. 



Ex. — Fig. 5 a of this article, originally described by Ffirster, 6i, from 

 the Gottingen collection. 



C. II. — Typical Janus monster, like the last but with the two head 

 components complete or nearly so. The laterally placed faces are in 

 reality the left half of one face joined to the right half of the other, as 

 explained above. Otherwise like C. I. 



Ex. — Fig. 5 b of this article, after L. Blanc ( I cannot find the origi- 

 nal of this). 



C. III. — Typical thoracopagi ; they evidently belong in the series with 

 the Janus monsters, from which they differ merely in the more complete 

 separation from above downwards, thus allowing the development of 

 two separate heads and necks. 



Ex.- — Siamese twins, Radica-Doodica. 



C. IV. — Separate duplicate twins, like A. VIII, but differing geomet- 

 rically in their mode of origin. This is probably the commonest type, if 

 we may judge by the frecpency of occurrence of thoracopagi. 



