1890.} The Extinct Sirenia. 699 
H. schinzii Kaup from the lower Miocene of Germany (Fig. 1a) is 
about as large as the manatee, while the Æ. forrestii Capellini is 
much larger, and is from the lower Pliocene of Italy. The Miosiren 
kocku Dollo is known from a skeleton from the Miocene of 
Belgium. It was rather larger than the manatee, and was 
nearest to the Halitheria. The principal difference is seen in 
FIG. r.—Dentition ot Halitheriidz, two-thirds natural size, from Dollo. Fig. a 
Helithet tum schinzii; 6, Miosiren kockii. 
the reduced last superior molar tooth, which shows indications 
of the reduction in number which took place in the dugong 
(Fig. 14). The largest species supposed to belong to the family 
is the Hemicaulodon effodens Cope, from New Jersey, which is 
known from a large superior tooth only. The dentine of this 
tooth has regular transverse ridges, which are also traceable in 
a Halitherium (Z7. capgrandi Lart.), and it is covered by a layer 
of cementum. As the molar teeth are unknown, the reference 
of this animal to this family remains uncertain. The most primi- 
