MR, W. K. PARKER OX THE STRUCTURE AND 
18 
outer fold the nasal canal is deep. The outer fold is not the same as in the last 
section ; it is not a valvular fold of the external nostril, but the beginning of the 
“inferior turbinal” ( i.tb .), and is formed as a pedate enlargement of the upturned 
wall. The cartilages protecting “Jacobson’s organs” ( j.o .) are no longer tubular, 
but form half a tube, open externally, the organ lying in the outer hollow. But the 
cartilages themselves have an osseous counterpart protecting them on the inner side, 
and having their shape and direction; these are the “ anterior paired vomers” (v'.) ; 
bones well known for their large development in the Ophidia and Lacertilia ; they 
do not represent a divided “ vomer,” proper, which in nearly all Mammalia is well 
developed also, and begins above these bones, as the next section well shows. Two 
pairs of “ crypts” are seen still, in section, and besides the large section of the nasal 
bones (: n .), we have the hinder edge of the premaxillaries (see Plate 2, figs. 6 and 8, px.). 
The palatal vault is very high here, it is partly occluded by the tongue (tg.), 
below which the lower jaws are seen each with its Meckelian rod ( mk .), its dentary 
bone (cl.), and its tooth socket (t.). 
8th Section (Plate 3, fig. 8).—This is through the angle of the mouth and the middle 
of the inferior turbinal. The septum nasi is here one-third deeper than in the last, 
and is more definitely bulbous below. The roof passes into a deep wall which ends 
in the inferior turbinal; this is two-lobed, now, and each lobe is convex in its mner 
and upper face ; the wall of the nose is sharp below the turbinals. 
The recurrent cartilage ( rc.c .) is largest at this part, and so are the small anterior 
paired vomers, but Jacobsox’s organ has the same diameter, nearly, as in the last 
section. Here the bifid fore end of the true vomer is cut across, close beneath the 
intertrabecular cartilage. The crypts ( gl.c .) still appear, so that there are two rows of 
them on each side. Here the section of the nasal (n.) is large, and the fore part of 
the maxillary (mx.) is cut across on each side ; this bone appears in two parts ; this is 
because of the beginning of the alveolar groove, which runs between the lateral and 
palatine portions of the bone (see Plate 2, fig. 6). 
The section of the tongue (tg.) is large here, and the dentary bone ( d.) outside 
Meckel’s cartilages (mk.) is in several laminae. 
9th Section (Plate 3, fig. 9).—This section, of which more than half is figured, and 
drawn on a smaller scale than the first eight, brings us into an increased complexity of 
the nasal labyrinth. The septum (s.n.) is like that of the last section, but the roof 
of the labyrinth is much flatter, and besides the more developed inferior turbinal, 
there is now the nasal turbinal (n.tb.), which runs obliquely from the roof to the side 
wall, enclosing a long ova] space. In the main channel, inside this space, there is a 
free section of cartilage, it is triangular, and has its apex looking upwards, this is a 
“precurrent process” of the middle turbinal (see also fig. 9a, pc.c.); it is equally 
developed in these types, and in the Insectivorous Hedgehog—its largest growth is 
seen in the Aard-Vark ( Orycteropus , Plate 15). 
This section is near the end of Jacobson’s organ and its related cartilages ; but the 
