1895.] The Significance of Anomalies. 133 
describes as pronator manus is Cryptobranchus Japonicus and’ 
of one described by Meckel in chelonians. It is curious that 
Macalister has found this arrangement in a tiger and I have 
found it in both arms of a chimpanzee, which I believe is an 
unique observation. This shows a tendency i in’ the carnivora 
and primates to similar variation which is not inherited. 
Some of these anomalies present a likeness that is very 
probably accidental, possessing no significance whatever. 
Such is the peculiar union of the different pieces of the ster- 
num by which the manubrium fuses with what should be the 
first piece of the meso-sternum. Is the fact that this frequent- 
ly occurs in the gibbons to be looked upon as anything but a 
coincidence? Does the occasional perforation of the thyroid 
cartilage by the superior laryngeal nerve in man derive any 
significance from the fact that this is found in the seal? 
Again, when we find in man some anomaly of the aortic arch 
or of the great arteries springing from it, we know that the 
usual course of development of the branchial arches has been 
disturbed. Need we look further than to sortie accident in the 
individual? Has the fact that the ab tis nor- 
mal in some animal any significance? These ‘are questions 
which admit of no certain answer. 
The second class of anomalies are those of most difficult 
explanation. They naturally suggest an analogy with the 
cases of the occurrence of similar structures in widely separ- 
ated animals, such as the bill of a duck and of the Ornitho- 
rhyncus, the paddle of the cetacean and of the ichthyosaurus. 
The obvious retort is that these resemblances are superficial ; 
but they are none the less true. Indeed, similar arrangements 
for a similar purpose are found which can in no way be called 
superficial Avery good’ example is furnished by Mr. 
Dobson.* cha! 
The Pyrenean water mole (Myogale) of the Insectivora, 
which has very elongated digits, has an enormously devel- 
oped fibular flexor and a rudimentary tibial flexor. On the 
true moles the tibial flexor ` is larger, but the arrangement is 
be Colsigaeative Variability of bäi and Muscles, etc. Journal of Anat. and 
Pin. T. XIX. p. 20. 
