180 DE. G. BATJE. 



I myself think that there is no doubt that the quadrate of 

 the lower Vertebrates is contained in the zygomatic process of 

 the mammals. 



According to Albrecht and Dollo, the quadrato-jugal is con- 

 tained in the malar (jugal). From what I find in a very young 

 skull of Dasypus, the truth of this assertion appears to me 

 doubtful. In this skull I find, on both sides, a perpen- 

 dicular fissure which tends to separate the articular surface 

 of the process together with the jugal. I think that this 

 half-separated piece represents the quadrato-jugal of the 

 Sauropsida ; to myself, therefore, it appears as probable that 

 this quadrato-jugal is included in the quadrate, an assumption 

 which is supported by the conditions found in Sphenodon. 

 Here, in older specimens, the quadrato-jugal is fused with the 

 quadrate, while it is free in the young form. 



The results of these observations I will summarise as fol- 

 lows : 



1. The assertion, put forward by Breschet and Peters, and 

 again by Dollo, that the cartilaginous distal portion of the 

 columella (stapes) of the Sauropsida is homologous with the 

 malleus of the Mammalia, is true. 



2. The malleus in the Sauropsida and the Mammalia belongs 

 to the first and not to the second visceral arch, that is, to the 

 epimandibular portion of Meckel's cartilage. 



3. The so-called hyomandibular or ceratohyal of Sauropsida 

 is nothing else than the epimandibular portion of Meckel's 

 cartilage (Peters, Albrecht, Baur). 



4. The " quadrate-cartilage" really belongs, not to the mandi- 

 bular, but to the palatine arch. (Albrecht asserted this.) 



5. The homology, asserted by Tiedemann, Platner, Kostlin, 

 Duvernoy, Albrecht and Cope, between the quadrate of the 

 Sauropsida and the zygomatic process of the squamosal, is 

 true. 



6. Probably the anterior end of this process represents the 

 quadrato-jugal. 



