394 ROBERT J. TERRY 



data on the history of the paranasal cartilage in mammals is 

 essential. 



As to the origin of the lamina supraconchalis and the broad 

 base of the naso-tm-binal, unfortunately little evidence was found. 

 The region of the side wall occupied by these parts corresponds 

 to that between the antero-inferior quarter of the paranasal 

 and the adjacent region of the parieto-tectal cartilage. I can- 

 not say to what extent, if at all, these two cartilages enter into 

 the lamina supraconchalis and naso-turbinal. 



One other matter should be mentioned with which, possibly, 

 the paranasal cartilage may be related — the origin of the in- 

 ferior oblique muscle. In the adult cat, this muscle arises from 

 the orbital surface of the maxilla behind the lacrimal bone 

 (Reighard, Jayne, Corning). In the embryo of 23.1 mm. its 

 origin is from a prominent angle of the lateral nasal wall, at the 

 junction of the paries nasi and plamun antorbitale. In the 

 17 m.m. embryo this angle corresponds with the ventral inferior 

 corner of the paranasal plate, overlapping the anterior margin 

 of the antorbital plate. Now, although no posterior maxillary 

 process is developed in cat in the stages studied, yet the angle 

 here referred to possibly represents this process. I have not 

 noted in the literature the origin of the inferior obhque from the 

 chondrocraniimi in mammals. Corning ('02), quoting Weber 

 on its origin in Lacerta viridis, says (p. 122) : ''Der M. obliquus 

 inferior 'entspringt von der Cartilago ethmoidalis, wo diese sich 

 an den Knochen der vorderen Orbital wand ansetzt.' " 



Lamina antorhiialis. Noordenbos is apparently the only one 

 who has observed in mammals the isolated origin of the carti- 

 lage forming the posterior part of the nasal capsule. This ele- 

 ment of the ethmoidal skeleton, found in mole embryos of 10.5 

 mm. and 11 mm., finds its parallel in the cat, where, as stated, 

 a separate plate of cartilage forms the planum antorbitale and 

 cupola posterior. Union between the antorbital plate and the 

 paranasal in the cat must take place rapidly, as no trace of an 

 interval between the two parts is to be seen in embryos of 20 

 mm. Complete union, that is, fusion, with the septal cartilage 

 is not present in the embryo of the stage modeled. Of much in- 



