52 JOURNAL OF COMPARATIVE NEUROLOGY. 
kindly permitted me to examine his specimen; and Mr. J. P. 
Hirt has made me an excellent photograph (of its ventral sur- 
face), roughly reproduced the accompanying drawing (fig. 4). 
It shows the complete and quite-typical rhinal fissure and the 
characteristic pyriform lobe. In its anterior part the rhinal 
fissure is fully a centimeter deep. 
The exact reproduction of these characters of the rhinence- 
phalon in an adult anosmatic Cetacean, and the presence of the 
olfactory bulb in the foetal Narwhal, show that these toothed 
Cetaceans were certainly (and probably quite recently) derived 
from ancestors presenting the normal mammalian type of olfac- 
tory apparatus. The absence of the olfactory bulb and pedun- 
cle in the Odontoceti cannot, therefore, be considered a just 
reason for adopting the utterly improbable suggestion of a nearer 
affinity of the Archzoceti to the Mystacoceti than to the 
Odontoceti. 
Estimated by the amount of sand which it displaced, the 
bulk of the natural cast (including that of a considerable 
quantity of matrix attached to the base of the brain and some 
small fragments of bone) is 410 c.c. If the necessary correc- 
tions and estimations be made from this gross cubic capacity, 
the weight of the brain in the Archzoceti must have been con- 
siderably less than 400 grammes, and perhaps nearer 300, as 
against that of the recent Cetacea, which ranges from 455 
grammes in Kogza (HASWELL) to 4,700 grammes in Balwnoptera 
(GULDBERG). 
