THE SKULLS OF FISHES AND AMPHIBIA. 203 



vertebra) of the spinal column coalesce into one mass with one 

 another and with the skull. The notochord, extremely large in 

 the spinal column, rapidly diminishes in size as it enters the 

 skull, and, becoming a mere thread, terminates behind the 

 pituitary fossa. The auditory organs are contained in large 

 postero-lateral projections of the cranial mass, with the outer 

 sides of which the suspensoria are connected. The base of the 

 skull is protected by a long parasphenoid, which extends back 

 under the anterior part of the spinal column ; in the dorsal 

 region it presents an anterior and a posterior pair of perichon- 

 drial ossifications, separated by oblong laminae from lateral bony 

 plates of the same character, but the homology of these bones 

 with those in the roof of the Teleostean skull is not, to my mind, 

 satisfactorily made out.* 



The suspensorial apparatus of Spatularia consists of a single 

 bone (A), compressed from above downwards superiorly, and 

 from side to side inferiorly, with a superior and an inferior car- 

 tilaginous epiphysis ; to the lower cartilaginous epiphysis the 

 operculum (Op) is attached, and a short thick prismatic cartilage 

 (B) is united by ligament with, and can play freely upon, its 

 anterior and inferior angle. Posteriorly the lower end of this 

 cartilage (B) is connected by ligament with the hyoidean arch 

 (Hy), w 7 hich consists of two portions on each side ; a small upper 

 piece, with which the flat bone (Br), representing a branchio- 

 stegal ray, is connected ; and a long lower ramus, the middle 

 third of which is bony, while the two ends are cartilaginous. 



Anteriorly, the lower end of the inferior suspensorial carti- 

 lage (B) is united by ligaments to two cartilaginous semi-arches 

 (D and Mn), of which the upper (D) is articulated by a trans- 

 versely convex head with a concavity of the lower (Mn). The 

 upper semi-arch is ligamentously united to its fellow in the 

 middle line, and is suspended by ligamentous fibres to the under 

 part of the prefrontal region of the skull. A long flat bone (E), 

 the hinder end of wdiich is cut off in the specimen figured, lies 

 on the outer side of the cartilage (D), and extends to the middle 

 line. A second long flat bone is closely applied to the inner 



* See " Spatnlariarum Anatomiam descripsit Tabulaquc iUustravit Albertus 



Wagner." Berolini, 1848. 



