BULLETIN OF THE UNITED STATES FISH COMMISSION. 457 



Growth of cakp. — Ou December 2, 1885, the size and weijiht of 

 two young c;ii"i) which were just 5^- mouths old, aud which were reared 

 at the carp ponds iu Washiugton, were as follows, as reported by Dr. 

 Hessel : 



The e;j:gs were obtained by methods which fixed exactly the day of 

 impregnation, which iu this case took place on June 15, 1885. 



Yakieties of German oarp. — The typical form of the species is 

 what is known as full-scale carp. From this, fish-culturists, availing 

 themselves of the tendency of all animals to break under domestica- 

 tion, and by exercising care in selection, have produced two well-defined 

 varieties, namely, the mirror and the leather carp. In the mirror carp 

 the scales are much larger and more irregular than in the full-scale 

 fish, and portions of the skin are without scale covering. In the ex- 

 treme form of variation, the leather carp, the scales have entirely dis- 

 appeared. Between the scale, the mirror, and the leather carp there 

 are an infinite number of intermediate forms, approximating more nearly 

 to one or the other of these distinct varieties. Neither the mirror nor 

 the leather variety can be maintained pure except by careful selection 

 in breeding. It will be found that the progeny of either the mirror or 

 the Iciither carp will present all the intermediate forms from scale to 

 leather. From each generation it will be necessary to select those Indi- 

 viduals for breeders which represent more nearly the form or variety 

 which it is desired to perpetuate. 



Distinguishing the sex of fish. — Mr. Martin Metcalf, of Battle 

 Creek, Mich,, writing on February 13, 1886, says : 



The experienced fish mauii)ulator can detect the male fish of almost 

 any family at sight, by reason of its smaller, cleaner, slenderer make, 

 narrower and more pointed muzzle, distance between the eyes, and other 

 inexpressible peculiarities, which when once recognized are almost un- 

 mistakable. 



How TO CATCH Crawfish. — The following will be of use to carp 

 culturists: (1) Take thirty to fifty osier twigs, or split white-ash sticks, 

 according to the size used, and 3 feet in length, form a bundle of 

 the whole and bind at each end with strong cord or wire, separate 

 the twigs or splints iu the center of the bundle by means of sticks 10, 

 15, and 20 inches long and forked at each end, so that when in i)lace 

 the trap will be spindle-like in shape, with the twigs evenly dis- 

 tributed about its circumference and center, and far enough apart to 

 allow eas3' entrance for the fish, but from which they will not readily 

 escape. Bait the inside with fresh meat of anj^ kind, only see that it 



