ZOOLOGY. 725 



mode of ingestion or selection of food. The skin constituting the pouch 

 it may be added, has a peculiar velvety appearance, and also reminds 

 one of the patagium or wing membrane of a bat. For a more detailed 

 summary of the salient characteristics of the type the memoir in the 

 Proceedings of the United States National Museum must be referred to. 



Variation in number of rays. — The numbers of rays in the various fins 

 generally afford a sure as well as easy means of diagnosing the species 

 and genera of fishes, and the variation is usually but slight, although 

 there is considerable difference in this respect. The number, however, 

 is the same in the young as adult. A most remarkable variation in the 

 number of rays co-ordinate with difference in size has, however, been 

 found in a fish of a very peculiar type, popularly known as the " king of 

 the herrings," and belonging to the family liegalecidae. This species — 

 the Regalecus glesne, or Banksii — is a deep sea fish which occasionally is 

 found as an estiay on the coasts of Northern Europe, chiefly after a storm, 

 and reaches a length of at least twenty-four feet. It has a loug, com- 

 pressed body, somewhat like a board, and on this account has been also 

 called deal-fish. Dr. Lutken and Professor Collett have lately- and in- 

 dependently studied this species, and the latter found that in compara- 

 tively small specimens {eg., 3,180 millimeters long) there are only about 

 218 dorsal rays, whde in a large one (5,647 millimeters long) as many as 

 406 dorsal rays were developed ; the tail, also, apparently becomes dis- 

 proportionately longer with increase of size. The ratio is by no means 

 exact between the development of the rays and increase of size of the 

 fish, but nevertheless it appears to be true that the tendency does exist 

 and becomes manifest on contrasting extremes in size and interposing 

 many of intermediate size. Such a development would be so anoma- 

 lous, however, that further investigations are necessary before the truth 

 can be considered established. (Christiania VidenskabsselsJcabs vorhand- 

 linger, 1883, No. 16.) 



The Orfe, or Golden Ide. — Four species of Cyprinids have been the ob- 

 ject of more or less cultivation in Europe : (1) the common carp (Cypri- 

 nus carpio), (2) the gold-fish or carp (Carassius auratus), (3) the ide 

 (Idtis melanotus), and (4) the tench (Tinea vulgaris). All have varieties 

 due to selection and cultivation, and of the last three reddish yellow or 

 golden colored varieties have been especially propagated. The golden 

 variety of the ide is known as the orfe, and has been introduced into 

 the United States as well as England. It is recommended as an orna- 

 mental fish superior to the gold-fish on account of " its larger size, live- 

 lier habits, and rapid reproduction," and " will thrive in all inclosed 

 waters suitable to roach and gold-fish"; it is also edible. (Nature, vol. 

 xxviii, p. 304.) 



The u Ahyu" or u Ai n of the Japanese. — In the ichthyological portion of 

 the Fauna Japonica, completed in 1850, Temmiuck and Schlegel de- 



