570 MR, M. F. WOODWARD ON [May 5, 
Cusps. 
The molar teeth of the adult belong to the trituberculo-sectorial 
type, the upper ones have square crowns bearing four cusps, i.e. 
3 large equal ones belonging to the trigon and a small postero- 
internal cusp or hypocone. The lower molars are elongated, con- 
sisting of a trigon and a very large heel with two conspicuous 
cones (hypo- and entoconid); the cones in the lower trigon are 
not equally developed, the protoconid being much larger than the 
other two. 
My specimen was too young to determine with any certainty 
the ontogeny of the cones, as only one of the main cones had 
made its appearance, the dental germ presenting the appearance 
of a high cone with a large posterior heel (metaconal region) and 
a slight internal extension. <A plan of the dental germ at this 
stage shows that structure to be roughly triangular, the main and 
only cone being situated at the anterior extremity and slightly 
nearer the external border. From the position of this cone and 
from a comparison with the cusp ontogeny as seen in the molar 
of Talpa, with which it is identical in pattern, I think one may 
conclude that this single cusp is the paracone, the posterior 
extension representing the metacone, while the internal shelf 
indicates the position of the future proto- and hypocone. 
In the lower jaw the main cusp is antero-external in position, 
and may be identified as the protoconid; a slight inward extension 
of the dental germ alone indicates the para- and metaconid, while 
a faint backward development foreshadows the future heel with its 
two cones. 
The probable order of cusp-development is thus shown :— 
1. Paracone. 1. Protoconid. 
2. Metacone. 9 Paraconid. 
3. Protocone. Metaconid. 
Entoconid. 
4. Hypocone. | Hipvecnat a 
A general examination of the Shrew’s teeth shows that with 
the exception of = and the almost undifferentiated 1st premolar, 
all the anterior teeth, viz. - 2 G. = ae, vo : exhibit the 
labially situated enamel-germ of a predecessor, some of these being 
in a highly developed condition, possessing marked dentinal germs 
but no calcification. These structures, from a comparison with 
the teeth of other Insectivora, must be regarded as vestiges of 
that earlier developed set of teeth the milk-dentition: this homo- 
logy is very striking when they are compared with the reduced 
milk-teeth seen in Hrinaceus, and is rendered -still more certain 
when we remember that there is indication of no other tooth 
replacement in the Soricide. 
il 
poe 
The relations of are very confusing, for the large develop- 
