66 



261. The eighth caudal vertebra of the Plataas arthriticm, in which a bony tubercle 



is developed upon both the neural and haemal spines, the latter being the 

 largest. Hunterian. 



262. Two specimens apparently of interneural spines of a Cheetodont fish, with the 



summits expanded into large oval bony tubercles, which show no articulation 

 for a dermal spine. Hunterian. 



263. A similar spine, apparently of the same fish, but with its summit much less 



expanded. 



In this, as in No. 262, the thickened summits are bent nearly at right 



angles with the spine. 



Hunterian. 



264. An interneural and dennoneural spine, joined together by the usual linked 



articulation. The interneural spine has an elongated pyramidal form with 

 four sharp ridges, one anterior, one posterior, and two lateral. Hunterian. 



265. An interneural spine supporting two dennoneural spines, by the usual linked 



articulation. The summit of the interneural spine expands into a very thick 

 irregular mass of osseous matter grooved posteriorly ; the dennoneural spines 

 are very short and thick. The specimen is probably from a species of 

 Ephippm. Hunterian. 



266. A similar specimen. Hunterian. 



267. A similar but smaller specimen. The interneural spine is less expanded at its 



summit in proportion to its length. Hunterian. 



268. A similar specimen, with the base of the interneural spine less expanded. 



Hunterian. 



269. A similar specimen, with the base of the interneural spine less expanded. 



Hunterian. 



270. A similar specimen, with the base of the interneural spine reduced almost to 



its normal proportions. Hunterian. 



