Hawaiian Monk Seal — King and Harrison 
comparison are considerably limited by the 
youth of the specimen. The form of this descrip- 
tion is based on that of the skeletons of M. 
monachus and M. tropicalis (King, 1956) and 
frequent reference will be made to the details 
in that paper. No skeleton of a young M. trop- 
icalis was available so the M. schauinslandi skele- 
ton was compared with that of an adult M. trop- 
icalis ( 1887.8.5.1.) and of a young M. monachus 
( 1894.7.27.3), the skull of which showed by its 
condylobasal length (224 mm.) and suture age 
(13) that it was from an animal of approxi- 
mately the same size as the Laysan monk seal. 
Comparison of M. schauinslandi Skull with 
Those of M. monachus and M. tropicalis 
1. The additional measurements now avail- 
able of the skull of M. schauinslandi confirm the 
previous statement (King, 1956) that skulls 
of both M. schauinslandi and M. tropicalis are 
slightly narrower in proportion to their width 
than those of M. monachus, though the accuracy 
of this conclusion is limited by the small num- 
ber of skulls available. 
M. 
M. tropi- 
M. schau- 
monachus 
calis 
inslandi 
% 
% 
% 
Zygomatic width... 
Snout width at 
59-9-70.3 
61.7-62.1 
60.9-61.5 
canines 
20.9-26.0 
20.6-20.9 
20.3-20.5 
Width at external 
auditory meatus 
Width at petrous 
53.1-58.5 
49.8-50.5 
50.5-55.0 
bones 
1 60.3-64.9 
56.3-59-2 
59.2-64.1 
2. The nasal bones of this young animal are 
as previously described from the type skull. The 
anterior ends are in the form of an inverted V 
with the point directed posteriorly; the posterior 
ends do not taper as much as in M. tropicalis. 
3. The lower edge of the infraorbital foramen 
is, when seen from the front, narrower than the 
upper edge. This confirms Matschie ( 1905 ) and 
is similar to M. tropicalis. 
4. The absence of a maxillary tubercle at the 
anterior edge of the orbit also confirms Mat- 
schie. 
5. As previously noted, the shape of the zy- 
gomatic arch is more like that of M. monachus 
than M. tropicalis. 
285 
6. It was noted previously that the posterior 
edge of the palate of M. schauinslandi formed 
a wide V. It is now felt that it is better described 
as U in shape and rather more like that of M. 
monachus, though there is probably a certain 
amount of variation in this character. 
7. The pterygoid bones curve outwards as in 
M. tropicalis and in this young skull of M. 
schauinslandi they are just visible when it is 
viewed dorsally. 
8. The coronoid process of the lower jaw is 
narrow and like that of M. tropicalis. 
9. Examination and comparison of the young 
skull of M. schauinslandi now available con- 
firms the previous report that it is more like 
M. tropicalis than M. monachus ( Fig. 3 ) . There 
are no supernumerary bones in the skull. 
Kenyon and Rice ( 1959) note that, in the 
few skulls of M. schauinslandi they examined, 
the shape of the palate and the shape of the 
zygomatic branch of the squamosal do not ap- 
pear to be constant and are thus not good dis- 
tinguishing characters. It is certainly agreed 
that the shape of the palate is variable and there 
is a need for the examination of as many adult 
skulls as possible to determine the amount of 
variation. 
Measurements of Skull of M. schauinslandi 
1958.11.26.1 
mm. % 
Condylobasal length 220 100 
Condylobasilar length 211 95.9 
Basal length 201 91.4 
Basilar length 192 87.3 
Snout width at canines 45 20.5 
Width of skull at front end of 
last upper molars 59 26.8 
Zygomatic width 134 60.9 
Width at upper edge auditory 
meatus .. 121 55.0 
Width at petrous bones 
(mastoid width) 141 64.1 
Palatal length 101 45.9 
Palatilar length 92 41.8 
Width of occipital condyles.. 62 28.2 
Length of nasal suture 50 22.7 
Length of upper molar row 55 25.0 
Suture age 13 
