1876.] 



PROF. T. H. HUXLEY ON CERATODUS FORSTERI. 



pterygium of Gegenbaur, I) is relatively small ; but the enlarged post- 

 axial cartilage (metapterygium, Mt) has extended upwards along the 



Fig. 11. 



ICHTHYOSAURUS 



MENOBRANCHUS $f, 2 \§j 



The left pectoral fin of Cestraciun philippi (letters as before), the left fore limbs 

 of Ichthyosaurus, Plesiosaurus, Menobranchus, and the left man us of Gecko 

 verus. 



I, humerus; 7?, radius ; U, ulna; r, radiale; /, intermedium ; u, ulnare; c, cen- 

 trale; c l , c 2 , c 3 , c 4 , c\ distal earpals; 1, 2, 3, phalanges of Menobranchus. 

 In Gecko it is uncertain whether x represents the intermedium and the ulnare 

 coalesced as in Menobranchus ( i v.), or whether x is the intermedium and 

 p is the ulnare, occupying the place of a pisiform bone. 



postaxial face of the first, until it has not only reached the articular 

 surface of the pectoral arch, but furnishes a large part of the articular 



