November 25, 1904.] 



SCIENCE. 



699 



emplified in the Asiatic breeds and the 

 bantams. 



Colors : Black ; biiff or red ; white ; brown 

 (in the female) the male being often 

 bronze, green, black, yellow and white; 

 barred (as in the Plymouth Rock) and 

 spangled (having center of feather of dif- 

 ferent color from periphery). 



Comb: Single, pea, rose (flat, covered 

 with tubercles, like a file) ; replaced by 

 crest. 



Legs : Feathered, f eatherless ; black, blue, 

 yellow, horn color. 



Body shape : Short and chunky ; tall and 

 slender. 



Now the various varieties of fowl are 

 made up of various combinations of these 

 characters. Thus we may have Plymouth 

 Rocks which instead of having bars are 

 pure white, or all buff ; or the single comb 

 may be replaced by a rose comb (when 

 they are called Wyandottes), the usually 

 clear legs may be feathered, and, finally, 

 they may be ' bantamized. ' 



Any desired characteristic in the whole 

 catalogue of poultry characteristics might 

 be engrafted upon an original Plymouth 

 Rock stock. "VVe might put on it the crest 

 of the Polish fowl or the twisted feathers 

 of the frizzle, or the loose barbs of the 

 silky, or the taillessness of the rumpless 

 or the long tail feathers of the Japanese 

 long-tailed fowl. All this is of course 

 possible because of the cross fertility of 

 the races having these different character- 

 istics. By similar procedure we might 

 make a white, blue-eyed, deaf, long-haired, 

 tailless, seven-toed cat; engraft the horns 

 of the Dorset sheep upon the hornless 

 Southdown; add the fecundity of the two- 

 nippled horned Dorset to the multinippled 

 condition of Dr. Alexander Graham Bell's 

 flock. "We might expect, after some ex- 

 perience, to do this with the same certainty 

 that we can get calcium chloride and car- 



bonic acid out of a mixture of hydrochloric 

 acid and marble. 



The bearing of this illustration, I repeat, 

 is to show us that characteristics of species 

 are entities not a little of whose interest 

 lies in the question of their origin in each 

 case. When we know how such character- 

 istics arise, then we may call them iorth 

 at will and so determine the evolution of 

 organic foi'm. For the present it is suffi- 

 cient that by the acquisition of new char- 

 acteristics new species have arisen from 

 preceding ones. 



This assertion is justified by the exam- 

 ination of any extensive synopsis of species. 

 Take, for example, de Bormans's synopsis 

 of Forficulidse in 'Das Tierreich.' Take 

 any synoptic key at random. Apterygida 

 japonica has two large tubercles at the end 

 of the abdomen. Apterygida allipes has 

 four small ones. Anisolabis xenia differs 

 from A. littorea by slightly smaller size 

 and especially by having two teeth in the 

 forceps in the male or three in the female 

 instead of none at all. I do not mean to 

 assert that species have arisen oiily by an 

 addition or subtraction of characteristics, 

 but this is a common method. Very often 

 we find one characteristic being replaced 

 by another. Thus in Lepidoptera one spe- 

 cies may differ from another in the re- 

 placement of red by yellow ; or one earth- 

 worm will differ from another by having 

 the sexual openings in different segments. 

 "We have no reason for thinking that these 

 characteristics are not integral entities" 

 as much as those distinguishing domestic 

 races. The modern morphologist, there- 

 fore, with the significance of characteris- 

 tics in mind must appreciate that in enu- 

 merating these characteristics he is enu- 

 merating the steps of evolution. 



The relations of morphology to embry- 

 ology are so intimate that the latter is com- 

 monly reckoned a subdivision of the for- 

 mer. Certainly the interpretation of the 



