370 ROBERT J. TERRY 



Regarding the course of the seventh nerve in the sulcus fa- 

 ciaUs, it is to be remembered that in adult Fehs domestica the 

 second part of the facial nerve traverses an open groove in the 

 medial tympanic wall (the rule in mammals), whose lateral bound- 

 ary is the ossified processus paroticus (crista parotica of van Kam- 

 pen, '04). Neither in the embryo nor in the adult does the free, 

 margin of the parotic crest incline toward the vestibular wall in 

 the formation of a canal. In Felis pf),rdus, however, the nerve 

 does run in a closed canal (Denker, '99). The groove in the adult 

 domestic cat begins anteriorly at the apertura tympanica and 

 terminates posteriorly opposite the level of the tympanohyale. 



Finally, reference should be made to the discovery by Spence 

 ('90) in the adult and new born cat of a bony or cartilaginous 

 support of the chorda tympani, projecting from the tympanic 

 bone. Bondy ('07) has confirmed this observation, finding the 

 process not only in cat but in a number of other mammals. No 

 evidence of the support was found in the stages described here; 

 its formation takes place according to Bondy, late in fetal life. 



Acustic nerve. Retzius ('84) described the nervus acusticus of 

 the cat as dividing into two or three chief branches, preferring 

 two in his account. I found this mode of branching in the cat 

 embryo of 23.1 mm.., and it may be remarked that, in our pres- 

 ent state of knowledge of the distribution of the acustic nerve in 

 the cat, the nomenclature of Retzius seems preferable to one 

 which attempts to represent the origins of the nerve fibers. For, 

 in the case of the ramus posterior, cells of the vestibular and 

 spiral ganglia are intimately associated, and no safe conclusion 

 on the origin of fibers of this ramus can be reached without fur- 

 ther neurological investigation. The small twig from the an- 

 terior ramus to the sacculus appears to correspond with the 

 ramulus maculae sacculi pars superior found by Voit ('07) in 

 Lepus. 



Orbito-temporal region 



Hypophyseal cartilage. Chondrification of the base of the 

 cranium in the hypophyseal region has been observed in several 

 mammals to take place independently of the rest of the chondro- 



