Hawaiian Monk Seal — King and Harrison 
287 
Dental formula ‘ C pC 
2 1 5 
The term "post canines” is used here instead 
of "molars” and "premolars,” as these latter 
cannot be used precisely when referring to pin- 
niped teeth. 
UPPER JAW TEETH: As previously mentioned, 
the upper incisors are set in a straight line 
across the anterior end of the premaxillae and 
in general the setting and shape of the teeth are 
like M. tropicalis. The incisors of this young 
animal do not have such a pronounced "waist” 
as those of the adult M. tropicalis, but it is more 
evident than in the young M . monachus. 
The canines are very small for a male animal. 
Those of the young Af. monachus, also a male, 
whose skull is only 4 mm. longer than that of 
the young M. schauinslandi, are much larger. 
M. mona- M. schau- 
chus inslandi 
Anteroposterior length at 
crown-root junction 15 mm. 12 mm. 
Anterior height of 
canine 23 mm. 14 mm. 
(in straight line from 
crown-root junction to tip) 
M. tropicalis also has small canines. The 
measurements given below of the upper canines 
of an adult male M. tropicalis (1889-11.5.1; 
condylobasal length 267 mm., suture age 25) are 
compared with those of an adult male M. mona- 
chus of approximately similar size (1863-4.1.1; 
condylobasal length 273 mm., suture age 26). 
M. mona- M. trop- 
chus icalis 
Anteroposterior 
length 16.5 mm. 11mm. 
Anterior height 27 mm. est. 17 mm. 
(v. worn) 
The height of the crown of the postcanine 
teeth in both M. tropicalis and M. schauinslandi 
is lower than in M. monachus and the main 
cusp is more rounded. In this respect M. schau- 
inslandi is more like M. tropicalis, but in the 
possession of a single anterior and posterior 
cusp it resembles M. monachus . The fourth post- 
canine has, however, two small anterior cusps 
and two small posterior cusps. The surface of 
the teeth is more rugose than in M. monachus 
and the anterior and posterior cusps are very 
much less distinct, as though it is in process of 
losing the second posterior cusps of M. trop- 
icalis. The postcanine teeth are not set obliquely. 
lower JAW TEETH: The lower incisors are 
similar to those of M. tropicalis, the canines 
are small, and the postcanines are similar to 
those in the upper jaw. 
No disease or irregularity in number is pres- 
ent in the teeth of either upper or lower jaws. 
Skeleton 
SCAPULA: The scapula of M. schauinslandi is 
very like that of M. tropicalis. It is similar in 
the way that the anterior edge is directed almost 
horizontally forwards from the neck before 
sweeping round to the dorsal surface. In M. 
monachus the anterior edge is directed forwards 
and upwards at an angle of approximately 45°. 
The spine in the young Laysan seal is repre- 
sented by a low ridge with a well-developed 
acromion process (Fig. 4b). 
HUMERUS, RADIUS, ULNA: No real compari- 
son can be made because of the youth of M. 
schauinslandi, though the humerus appears to 
be slightly more robust than that of M. mona- 
chus of similar size. 
MANUS: Except that the terminal phalanges 
are not so extensively grooved for claws as in 
the young M. monachus, although the claws 
themselves are of approximately similar size, the 
manus is not noticeably different in the three 
species (Fig. 4c). 
PELVIS: The pelvis is very similar in shape 
to that of the young M. monachtis although it 
is more mature as there is no sign of the sym- 
physis between ischium and pubis, and the 
acetabulum is deep and well formed, while in 
the young M. monachus the symphysis is about 
half fused and the acetabulum is shallow and 
more obviously immature. The shape of the 
ischium and pubis is like that of M. monachus 
except that the pubis is possibly slightly more 
slender. There is no sign of the stout pubis and 
very narrow ischium posterior to the ischiatic 
spine as in M. tropicalis. The ilium is slightly 
narrower than in M. monachus. There is a large 
foramen for the obturator nerve just posterior 
