120 GEO. S. HUNTINGTON 
ihnen ist die primire? Nach allem, was die Entwicklungsgeschichte 
der Organe bisher zu Tage oefardert, sicher eine der symmetrischen. 
Zwischen den beiden, die zur Verfiigung stehen, wird die Wahl dadurch 
wesentlich erleichtert, dass in der einzigen Lunge, welche der epar- 
teriellen Stockwerke entbehrt, auch die hyparteriellen eine hochgradige 
Verkiimmerung erlitten haben. Dadurch gewinnt die ganze Bildung 
den Charakter eine Reductionsform, deren Ausgangspunkt auf breiterer 
Grundlage gesucht werden muss. Eine solche ist der Bronchialbaum 
mit eparteriellen Bronchen in beiden Lungen. Auffallig bleibt dabei 
immerhin, dass gerade diejenigen Saéugethiere, bei denen man am ehes- 
ten geneigt sein méchte, den Besitz einer Grundform vorauszusetzen, 
némlich die Monotremen und Beutler, sie nicht besitzen. Sollte da 
nicht von der Ontogenie Aufschluss zu erwarten sein? 
It is difficult to find an adequate reason for Aeby’s assump- 
tion of a ‘hochgradige Verkiimmerung’ of the bilateral hypar- 
terial bronchial tree in Hystrix cristata. It may have been due, 
as his figure suggests, to the fact that he examined this lung by 
dissection and did not have the control afforded by a good cor- 
rosion preparation. The lung of Hystrix is unique among mam- 
mals in its type of lobation. ‘The entire organ is split up into 
numerous small polygonal lobules and is likely to give the impres- 
sion of a somewhat abortive structure when handled. It pos- 
sesses the delicacy and friability characteristic of many rodent 
tissues, and is very liable to injury during manipulation, pre- 
venting its complete distension. The suggestion of deficiency 
which Abey received is also fostered by the minute size of many 
of its lobular subdivisions, the organ resembling in the plan of 
its organization, e.g., the sea-weed like liver of Capromys pilor- 
ides, and by the fact that the proximal segments of the stem- 
bronchi are included, at least in many individuals of H. cristata, 
within a widely expanded tracheal bulla, in place of the typical 
bifurcation. 
That the reduction of the lung assumed by. Aeby does not 
actually obtain in the bilateral hyparterial type, is abundantly 
proved by the rich unfolding of the bronchial tree shown in good 
corrosion preparations. The foregoing review shows that Palae- 
ontology, Palaeozoology, Ontogeny and Comparative Mor- 
phology are at one, as far as the available evidence goes, in 
refuting the claim to primitive archeal character made in behalf 
