SKULL OF A HUMAN FETUS OF 40 MM. 419 



The goniale (figs. 1-2) is a short, somewhat flattened, rod of 

 membrane bone, lying immediately below and medial to the pos- 

 terior fusifomi enlargement of Meckel's cartilage, and so close 

 to the latter that it appears to be developed from the perichon- 

 drimn covering its surface. Its long axis is parallel with that 

 of Meckel's cartilage, and its anlage is quite separate from that 

 of the tympanic, which lies on a lateral and caudal plane. Its 

 posterior end approaches close to the neck of the malleus, but 

 does not actually become continuous therewith until the end of 

 the fifth month (Broman '99), when it becomes the anterior or 

 Folian process of that ossicle, a fact which was demonstrated by 

 Dreyfuss ('93). Gaupp ('05 and '11) has given strong reasons 

 for the identification of the processus Folianus with the goniale 

 of the reptiles, and it is on his authority that I have used that 

 name for it here. The bone is shown in the Hertwig model, 

 and also appears in Low's illustration from a 95 mm. human 

 embryo under the name of 'processus folianus.' 



The vomer (figs. 2, 16, 17 and 18) is represented by two slender 

 strips of bone lying one on either side, immediately caudo- 

 lateral to the lower border of the mesethmoid, the two almost 

 enclosing this border excepting for a narrow strip between their 

 lower edges. The dorsal extremity of each strip is blunt, but the 

 ventral is drawn out to a fine point, and near the latter there is a 

 bridge between the two bones. The ventral point projects 

 only a short distance in front of the dorsal border of the larger 

 Jacobsonian cartilage. 



The maxilla (figs. 2, 4, 16 and 17) is an irregular mass of 

 cancellous bone which lies in a notch on the ventro-lateral aspect 

 of the ectethmoid, and it already shows the frontal, alveolar, 

 palatal and zygomatic processes. The central mass of the bone 

 is irregularly triangular in form upon coronal section (fig. 17), 

 the longest side of the triangle being applied to the ethmoidal 

 cartilage, while the medial angle represents the palatal process, 

 the upper angle the frontal process, and the remaining angle, 

 which is a right angle, the alveolar process. The pointed, up- 

 wardly-directed frontal process reaches a level somewhat above 



THE AMEHICAN JOOKNAL OF ANATOMY, VOL. 16, NO. 4 



