Tlie literature on coii joined twins is exteusivc. T'hc papers that arc oLdainable liere she\ 110 similarity to 1hr3 one which 1. The twins ai*c female, j o i i i d together from 1 notch to the nnihilicus. 'rhe nmbilicxl cord is singlc bui appears a s the fusion of two cords; at tho placental eritl they are separated for a distance of 40 mm. with wmuioii left beiw--ec.n. 'l!lie pcviliarity of this monster is that one of the Iwins has hawlip and clcft palatc wbilc-the other has R ~iorniwlly developed factk. The deformity appears on 1 lie left side of the face, the nosti~il of that sidc is deformed by tht. f o i ~a r d a d medial inclination of the left medial illcisor. Oil operiirig the whdomw the livei*s are found joiiietl together.
From measuremelit ilic 155 ins B P P ricbarly equal in size, none caii be called thc parasite of the other.
N~winau ( ' H ) , from his stntly on Trsils armadillo, belirves that the failure of the closeiwss of' rcwrnl,latic~c betwcm moiiozygotic 2inman twins is due to Cli~ s q p g a l i i i g of imjt c h ractcrs by somatic dirisioiis. The resiilt is the iiicqnality of distribution of thc determining: factors during clcavag~s. This q)ecimen supports Ilk explanat iori I ~c a u s c Iiarelip and clcft palate are iriliri*it etl arid have Iwcn knowii t o o<:cur in several inembrrr: of the same family a s cited by ~a l l ~~i i t y i i ~~ i s inherited as il recwsivc. mtwdcliaii c*harac*tei.. Recd ( '33) ~I I liis firrth(~r investigtitioii of' the c~rnhl*yology of h i l r ~l i p ant1 157 LITERATCRE CITED RAIJAN'CYNIC, J. W. 1904 bft~rrual of anteuatal pathology and hygiene. The N ~u M -, H. H. 1924 The biology of twins, 2nd cd. Univ. of Chicago Press, REED, S. C! . 1933 An embryological study of liarelip in micc. h a t . Ree., REED, S. 0. AND G. D. SNFLL 1931 Harelip, a new mutation iu the house mouse. embryo. Williams Green and Suns, Ediuburgli.