* 
+ cept be' erat as separating the heart into two absolutely 
REMARKS ON 
difform organs. Or, if we say that the duplex heart, like 
the thoracico-ventral cavity gives example of how duality 
becomes fused into unity, then we call such a creation 
unity in either case, whether it existed formerly as dual 
not 
But at present we are only remarking upon the skeleton 
quantity, and, in reference to this, we observe, that the 
ber of cost is not constant even in the human skele- 
ton,* and that, between thoracic series and the pubic arch, 
exists a hiatus in general series, caused by the loss of 
costal parts. This hiatus is the ventral region, and in it 
we trace the fibrous analogues of sternal and costal struc- 
tures, at the same time that we see it to be bounded 
laterally by asternal costal forms, which, (from 4, to g, in 
THE FIGURES OF PLATE XXXV. 3 
each of the opposite eee pointing towards the ventral 
median line, or linea alba, manifest a graduated failure of 
quantity in reference to this line. And taking thoracic 
costal series as the plus standard of comparison, and as 
meeting at a sternal structure, we observe that the asternal 
or ventral series, being minus quantities, do not, for this 
reason, meet at a ventral sternum, and that the venter is a 
design accordingly. For if the asternal costze persisted in 
plus quantity, the ventral region would not exist. In short, 
if absolute plus uniformity, which we take to be the prime 
model, existed in figs. A, B,C, D, E, F, G, H, they would fall 
as far below the standard of fitness, by having a costal series 
extended over the abdominal region, as if the now persist- 
ent thoracic series had also undergone the like metamor- 
phosis, and presented in ventral character for a human form.’ 
* The doubt, which is expressed in the following quotation, as to the number of ribs developed in the human skeleton, is owing to the 
te circumstance of nen anatomy not having been studied by the ancient Greeks. But it may also be here remarked, that, even to the present day, 
_ which envelopes these facts of creation, except by a generalisation 
- now that special anatomy has obtained the fullest account of all the possible facts of ossific formation which have ever been developed upon the 
human type, still it remains impossible for the anatomist, whether special or comparative, to say, with certainty, ‘how many costal forms of 
sternal or asternal character stand created within any living human figure. The same doubt attaches to the number of serial quantities, whether 
‘of the entire axis or of any region of that axis. Nor can the anatomist, whether special or comparative, ever hope to clear away the mystery 
Aristotle, the founder of generalisations, has observed as follows :—‘‘ Under- 
neath are the loins, which are opposite to the belly ; but. the ribs, which are, on each side, eight in number, are common to both the superior and 
inferior parts, for, with respect to what is reported of the Lychnians, that ore have only seven ribs, we have not heard this asserted by any one 
who is worthy “ belief.”’—See History of Animals, book 1, p. 28. 
Hess Thus, therefore, the parts in the external superficies of the human body are arranged, and as we have said, they are especially denominated 
and known from custom. The contrary, however, is true of the inward parts ; 
for, of all the parts belonging to-man, they are the most unknown, 
so that it is necessary to survey them by referring to the parts of other animals to which they are similar.”—Aristotle, History of Animals, ° 
book 1, p. 29. 
