PRESIDENT S ADDRESS. ll. 



segmented ; the notochord is surrounded by a series of 

 cartilaginous rings, some of which are partly calcined. This 

 feature, together with the continuity of cranial cartilage, shows a 

 relationship with the Ganoids and the Dipnoi. The living 

 Chimceras are few in number and of comparatively small dimen- 

 sions, not exceeding a length of five feet. In living forms the four 

 gill-clefts are covered by a fold of the skin. Like the Dipnoids 

 each jaw is armed with a pair of broad dental-plates, with the 

 addition of a pair of smaller cutting teeth in the upper jaw. 

 Unlike the Shark the mouth is always terminal. The fins are 

 similar in structure and position to those of the Sharks, also in 

 the absence of a swim-bladder. This genus is represented by 

 three species ; C. momtrosa, from the coasts of Europe, Japan, 

 and the Cape of Good Hope ; C. colliei, from the west coast of 

 North America ; and C. affinis, from the coast of Portugal ; 

 Chimccroids are principally found in the Mesozoic and Tertiary 

 formations. In the genus Callorhyncus we have apparently the 

 most specialised representative of the group with crushing teeth. 

 It is represented by an existing species in the seas of the 

 southern temperate zone. Another Chimaeroid, Myriacanthus 

 paradoxus, known by its spines and teeth, has been found in the 

 Lower Lias of Lyme Regis. 



Sqv-atinida. There is only one solitary representative of this 

 once considerable family of the Shark tribe, Squatina [RhinaJ 

 angelus, the Angel or Monk-fish, which is not unfrequently caught 

 on our coast. Squatina occurs in the Lithographic Stone of 

 Solenhofen, Kimmeridgian, also in the Upper Chalk and the 

 Eocene. 



Notidanidcc. Lateral teeth, comb-like, inclined backwards. 

 The primitive morphological position oiNotidanus is shown by the 

 persistent notochord and the character of the skull, which is only 

 very slightly removed from the original type. The teeth of this 

 group have been found in the Jurassic and later formations. 

 Four living species are known, which are distributed over nearly 

 all the tropical and sub-tropical seas ; their average length is 

 about fifteen feet. 



