566 B. F. Kingsbury and IT. D. Keed. 



quadrate. This is evidently the columella ; an operculum was not 

 recognized. A text figure of a section through the ear capsule 

 recalls strongly the similar section in just transformed Chondrotus 

 (PI. IV, Fig. 38), already described. 



Salamandra. 



Salamandra maculosa has proved to be a form of rather unusual 

 interest with regard to its sound-transmitting apparatus both in 

 respect to the elements present and their relations Avhen considered 

 in the light of conditions in other forms. 



The skeletal elements of the head of Salamandra are quite fully 

 ossified. The os quadratum is composed of a thin outer shell of 

 bone very closely associated with the under surface of the superim- 

 posed squamosum. Underneath the os quadratum is the palato- 

 quadrate which is continued into the basal, otic and trabecular (as- 

 cending) processes. As has been pointed out by Wiedersheim ("77), 

 the inclination of the supensorium to the long axis of the skull is 

 almost transverse, a condition not met with in many salamanders. The 

 inclination of these elements, whatever its cause, undoubtedly influ- 

 ences the nature of the suspensorio-columellar connection in all 

 forms. 



Both columella and operculum are present in the adult. The 

 columella is a plate of partly calcified cartilage fused with the lips 

 of the fenestra vestibuli except in the caudal third of its circum- 

 ference where it forms the cephalic margin of the definitive fenestra. 

 Fig. 40 (PI. V) is a photograph of a section through the cephalic 

 portion of the columella and shows how completely it is fused with 

 the ear capsule in this region. In the same figure is shown the short 

 and thick stilus which projects from the dorso-lateral aspect of the 

 columella. It is composed of hyalin cartilage distally continuous 

 with the cartilage of the palatoquadrate ; proximally it passes over 

 into the plate of the columella whose cartilage, calcified where it 

 joins the ear capsule, may also be seen in this figure. To the squa- 

 mosum it is joined by connective tissue representing a short ligament. 

 Describing the "stapes" in Salamandra, Parker ('82a) observes: — - 

 (pp. 1Y4-5) "There is a well ossified lip, like the mouth of a pitcher. 



