Temperature and Vertebrae 33 



ther. He noted that among the Labridoe, the species of 

 temperate waters had more vertebrse than those of the tropics. 

 He says \'^ 



In those genera of Labridcr which are composed entirely or for the 

 greater part of tropical species the vertebral column is composed of 

 twenty-four vertebrse, whilst those which are chiefly confined to the 

 temperate seas of the northern and southern hemispheres have that 

 number increased in the abdominal and caudal portions. 



GUI, 1863. — Shortly after, in a review of Dr. Giinther's 

 work on the Labroids.f Dr. Theodore Gill showed that this 

 generalization was not confined to the labroids alone, but 

 that "it may also be extended to other families. * ^ * This 

 generalization is applicable to the representatives of acan- 

 thopterygian;|: families generally, and can be considered in 

 connection with the predominance of true malacopterygian§ 

 fishes in northern waters, fishes in which the increase in the 

 number of vertebrae is a normal feature." 



Gill, 1864. — Later, 1 1 Dr. Gill remarked that the increase in 

 the number of vertebrae of Sebastes, a genus peculiar to the 

 northern seas, affords an excellent example of the truth of the 

 generalization claiming an increased number of vertebrse for 

 the cold-water representatives of acanthopterygians. 



Jordan, 1886. — In 1886, in a paper before the Indiana Acad- 

 emy of Sciences,^ the present writer showed that in very 

 many families the number of veterbrae decreases as we ap- 

 proach the tropics. So constant is this relation that it was 

 thought that it might almost be termed a law. The writer 

 could however suggest no adequate cause by the operation of 

 which such changes are brought about. 



Jordan and Goss, 1889. — In a study of the flounders, in 

 1889,** a table was given showing the numbers of vertebras in 



* Catalogue of the Fishes of the British Museum, vol. iv, p. 65. 

 t On the L/abroids of the Western Coast of North America, Proc. Ac. 

 Nat. Sc, Phila., 1863, p. 221. 

 J Spiny -rayed. 



I Soft-rayed ; here including the anacanthine fishes. 



II Proceedings Academy Natural Science, Phila., 1864, 147. 

 II Still unpublished. 



** A Review of the Flounders and Soles {Pleuronedidcs) of America 

 and Enrope, by David S. Jordan and David K. Goss. 



