de"vt:lopment of the skull in the pig. 



325 



hooked portion (" hamular process ") being the apex of the pterygo-palatine arch. The 

 top of the pterygoid, behind the mesoptcrygoid, has ah-eady coalesced with the pos- 

 terior sphenoid at the root of the " ala," and externally also it is almost completely 

 confluent with the " external plate " {e.pg.). 



The thin dentate end of the vomer (Plate XXXVL fig, 4, v.) ends at the same trans- 

 verse line with the mesopterygoids, whilst in front it reaches the fore margin of the 

 premaxillaries within a barleycorn's length. The vomerine plate broadens a little to sit 

 on and articulate with the upturned and dovetailed edge of the palatine plate of the pala- 

 tine bones, and also with the longer " harmony suture " of the maxillaries ; its groove 

 for the trabecular subseptal beam is rather deep. The complex nasal labyrinth is well 

 ossified, but the septum between the inferior turbinals, supplied by the fifth nerve, is 

 still soft. Beneath the large lacrymal, the "lamina papyracea" of the ectoethmoid 

 is just seen beside the pupiform socket of the developing last molar tooth. 



The lacrymal (Plate XXXVII, fig, 1, 1.) is a notable bone on the outer cheek 

 with an upper and a lower canal ; it is deeply scooped where it articulates antorbitally 

 with the orbital plate of the frontal (Plate XXXVII, fig, 1, /.,/,); it forms part of 

 the anterior root of the zygoma, and is nearly equally developed both within and with- 

 out the orbit. 



The malar or jugal {j.) is a massive bar of bone, strongly set in at the front of the 

 orbit between the lacrymal and maxillary (Plate XXXVII, fig, I., ni.). It is saddle- 

 backed in its front thicker part, and its hinder half suddenly becomes only as thick as in 

 front, so that the squamosal may yoke on to it ; its lower surface is arcuate, its inner sur- 

 face scooped, and its outer surface convex : almost an inch of space intervenes between 

 the highest part of the malar and the descending postorbital spur of the frontal. The 

 proper temporal bone, fitting scale-like to the temporal region of the skull, over the 

 hinder edge of the frontal and the lower part of the parietal, is properly called the 

 squamosal (s^.). This temporal part turns suddenly outwards to catch the pyriform 

 condyle of the lower jaw, and then runs forwards and rides on the upper edge of the 

 malar, stopping behind the concave portion of that bone. This zygomatic process of the 

 squamosal rises sharp above the transverse " glenoid " bridge, which is scooped above 

 and below, has a convex transverse part in front, and an angular scooping behind : this 

 part is clothed with articular cartilage, and the mandibular condyle rides freely under 

 and up it, a meniscus intervening. 



There is an acute ridge which runs obliquely up to the upper third of the superoccipital 

 (Plate XXXVII, fig. 1, sq., s.o.) ; this rising wall closes in the deep temporal fossa. 

 This ridge of bone, running downwards also, binds strongly upon and coalesces with the 

 rough rounded uplooking mouth of the " meatus auditorius externus" (m.e.). Below this 

 part the squamosal splits into two narrow rough leaves; the hinder of these is the 

 " posttympanic process," and the front leaf is the " postglenoidal." The latter binds 

 upon the side of the tympanic (ty.), the former runs down the fore edge of the par- 

 occipital (paramastoid) process (jj.oc.), and scoops its upper third. In front of the 



