^^^ ZOOLOGY, 



ilurmg-a voyage from San Francisco to Yokohama, and maintains (1) 

 that he saw them out of water " when the air was almost motionless " and 

 that, m fact, they were not mnch, if at all less numerous on such occasions 

 than when there was a moderate wind"; (2) that the flapping move- 

 ment IS quite regular and very rapid ; and (3) that this movement -may 

 he confuiued^^ for the whole or a part of the flight, but is generally discol 

 tmned after the first few rods, and the course completed by a pui^ 

 skimmmg or sailing movement." It is further claimed that - the course 

 of the flight IS generally in a straight or curved line," but is sometimes 

 abruptly changed^ ^ apparently by the aid of the tail,'' or rather hetw 

 lobe of the caudal fin. The average flight, it is thought, -does not per- 

 haps exceed fifteen seconds, nor extend ahoxe four or five hundred feet"- 

 the longest observed "lasted not less than forty seconds, and its extent 



Prof ]). S. Jordan also carefully examined the flight of an -Ea^occetus 

 {1. cakronucus) m the waters of Southern California.* He observed it 

 best in early morning when both air and water were free from motion." 

 On rising from the water the movements of the tail are continued for 

 some seconds until the whole body is out of water. While the tail is in 

 motion the pectorals are in a state of very rapid vibration, and the 



and ^entrals are spread, and, as far as we can see, held at rest. When 

 the hsh begins to fiill, the tail touches the water and the motion of the 

 pectorals recommences, and it is enabled to resume its flight, which it 

 finally finishes by falling in the water with a splash." The flight was 

 thought to sometimes extend to "nearly a quarter of a mile." 



AFFINITIES OF PLEUEACANTHUS.f 



In the Carboniferousand Permian deposits have been found the remains 

 of fishes described under the name of Pleuracanthus, whose affinities 

 have been involved in considerable doubt. They have been mostly re- 

 ferred to the Selachians, although suggestions have been made that 

 they may belong rather to the Teleosts. The question has lately been 



tTatTov l" '" ^'"" '^' '''^^^^^' ^^^ ^^ ^- --^ t« t^^ --^u«^o" 

 that the:^ claim a nearer relationship to the Teleosts than to the Elasmo- 



branchs, although there is equal reason to believe that they possess 



many characteristics in common with the Sharks and Pays and he 



The tw^'Ti:"!^ l^l^^^*^^,r- - - intermediato positio'n' between 

 he two. The affinities he thinks are decidedly on the side of the Silu- 



Zt''o-r./ '' reasonable, he thinks, to consider them as forerunners of 

 that great group of fishes. 



_ '^ It remains," he says, " to be seen what were the successive steps in 

 "^^^^^i^^^ pp. 804, 805. 



4:^^.^i:j:i,;t^^;r3:s^:^""^^^^ - *^^ -- —ant... .«„. 



