326 
A MEMOIR UPON THE GENUS 
bent doAvnward with its superior and inferior surfaces concave. The postorhital 
portion of the malar is thin and bent inward. This portion of the zygomatic arch 
is weakly developed as compared with that of P. paludosus. The malar post- 
orbital process is large and sharp. 
Maxillary. — The ascending plate of the maxillary is vertical and its surface is 
plane ; its antero-posterior diameter is not greater than its vertical, owing to the 
very short facial region of this species. The portion of the maxillary forming the 
floor of the orbit is broad and deep, much more so than in P. paludosus. The 
antero-posterior extent of the orbital floor is much greater than in the larger 
species, and in this character P. megarhinus agrees with Telmatotlieriuni. The 
prominent canine aveolus forms an abrupt termination to the maxillary region 
anteriorly. The infraorbital foramen is large and situated above the first true 
molar. The large lamina between the nasal notch and the orbit is formed mainly 
by the naso-maxillary articulation. A small opening at the antero-superior part of 
the orbit is evidently for the lachrymal duct. Its opening is small, and the lach- 
rymal bone probably only formed a small part of the cheek as in the skull of 
the Tapir. 
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Figurk 6. — Comparative views of the occipital region. 1. Limnohyopx laticepx. 2. Pidpeoxijiipx paludoxim. 
3. PalxQsyiypx megarhinm. One-fifth natural size. 
Foramina . — The condyloid foramen is large in P. megarhinus and is situated 
nearer the foramen magnum than in P. pahidosus. The foramen lacerum posterius 
and medium are fused with the large lateral vacuity. The foramen ovale is 
large and situated about an inch in front of the foramen lacerum medium. The 
posterior opening of the alisphenoid canal is about seven-eigtlis of an inch below the 
foramen ovale. The antero-posterior extent of this canal is nearly twice as great 
as in the Tapir. The portion of the sphenoid fonning the outer walls of the alis- 
phenoid canal is strongly convex and very prominent. 
Cranial cavity. — The general form of the cerebral cavity in this species is an 
elongated oval, with a very much reduced vertical diameter. This is strikingly 
apparent when we compare the cranial cavity of a Tapir with that of Palceosyops 
