156 MR. W, K. PARKER ON THE STRUCTURE AND 
incus (s.¢,7.) is unusually short ; the long crus (/.c.2.) is also short, but is well inturned, 
and has an oval facet for the head of the stapes. 
That bone (s¢.) is rather high, has a long oval base, narrow, and somewhat snagery 
sides, and has a tubercle on its neck, in which is a very rudimentary interhyal 
(i.hy.), rooted in the base of the stapedial muscle’s tendon (st.m.). 
Highth Stage of the Skull of Erinaceus europzeus ; nearly adult. 
This skull is, conceivably, a very gentle modification of the type we are familiar 
with in the Marsupials; it is just fairly within the Hutherian margin. The upper 
and side views (Plate 21, figs. 2, 3) show that most of the sutures are still present, and 
that where the sagittal is dying out, there a crest is forming between the top of 
the large temporal muscles. Also a lambdoidal crest is seen behind the wide 
interparietal (¢.p.), which, however, is confluent with the proper supraoccipital 
(fig. 4, s.0.). The coronal suture is W-shaped, the bones being strongly dovetailed into 
each other. The large, long nasals (n.), narrow behind, take up about a third of the 
gently arcuate dorsal line of the skull; the frontals (f) flank them in front, but do 
not reach the large ascending plate of the premaxillaries (pw.), the much larger 
maxillaries (mx.) intervening. An oblique ridge separates a deep fossa above from 
the large lachrymal passage (/.c.) below; this passage is on the edge of the orbit, but 
most of the bone, now largely fused with the maxillary, is inside the orbit. The 
orbital space opens freely into the temporal fossa, and the outlines of the bones that 
form the whole of this concavity can be well seen for the most part, the fusion of the 
lachrymal with the maxillary being exceptional. Down at the base of the orbit the 
orbitosphenoid can be seen passing within the alisphenoid, and some distance outside 
the former the alisphenoid and maxillary meet and form a narrow longitudinal bridge 
over the thick edge of the palatine bone (pq.). 
The infraorbital foramen (V*.) is large, and so is the canal that runs backwards into 
the skull through the hinder part of the sphenoidal fissure, for the alisphenoid 
(Plate 20, fig. 6, a/.s.) is deeply grooved for this large 2nd branch of the 5th nerve. 
The jugal (j.) is moderately strong; it reaches the glenoid fossa, but is sharp 
there ; it does not dilate, terminally, as in the Marsupials. Part of the basis cranii and 
the auditory ring can be seen from the side view, but the lower view (Plate 21, fig. 1), 
alone, displays these parts well. The premaxillaries and maxillaries (pa., mx.) at their 
palatal junction leave a considerable space (a.pf), right and left, through which the 
recurrent cartilages and J ACOBSON’s organs can be seen. The palatine processes of the 
premaxillaries are long but lie above those of the maxillaries ; they have added to their 
substance and length, the antero-lateral vomers or splints of J AcoBsoN’s organs. The 
palatine plates of the maxillaries form a fine large concave roof; they are followed by 
the imperfect plates of the palatine bones (pa.). The fenestra seen in each bone in the 
5th stage (Plate 20, fig. 1, pa.) is now a deep notch open in front, for each palatine bone 
is now formed in its lower part and fore half intoa flat fork with long ragged “tines ;” 
