898 H. H. NEWMAN AND J. THOMAS: PATTERSON 
the data has been presented and the underlying problems pre- 
sented for discussion. 
Set 64. (Mother normal). Foetus 1 appears at first sight to be 
perfectly normal, in so far as band arrangements are concerned; 
but examination reveals the presence of ten full bands. In view 
of the fact that all of the other members of the set show more or 
less extensive regions of splitting in the first band we are forced 
to conclude that the extra band in this individual has been pro- 
duced by a process of band splitting carried to a completion. 
Fig. 3 Diagrams of the ‘abnormal’ bands in the four foetuses from female no. 
64. In this as in the two succeeding figures, the Roman numerals I-1v refer to the 
individual embryos from which the sketches were made, while the arabic indicate 
the number of scutes in each of the regions to which they are adjacent. 
This is really only a bilateral expression of the condition seen in 
the right hand half of the first band of foetuses m1 anditv. That 
there are 64 scutes in the first half-band and only 62 in the second 
might seem to militate against the idea of splitting, but there 
occur in our collection several undoubted cases of splitting where 
the number of scutes in the two series produeed by the split are 
unequal. The split first band of foetus 1 is shown in fig. 3, I. 
