1882.] DR. VAN DYCK ON SYRIAN STRKET-DOGS. 369 



causes ; and these modifications of structure &c. differ in different 

 species under apparently the same conditions. Statements of this 

 nature have sometimes been misinterpreted, as if it were supposed 

 that variations were indefinite or fluctuating, and that the same 

 variations occurred in all species. 



In reference to sexual selection, I will here only add that the 

 complete manner in which the introduced dogs and other domestic 

 animals in South America and other countries have been mongrelized, 

 so that all traces of their original race have been lost, often appeared 

 to me a surprising fact. This holds good according to Rengger' 

 with the dogs even in so isolated a country as Paraguay. I formerly 

 attributed this mongrelization merely to the breeds uot having 

 been kept separate and to the greater vigour of cross-bred off- 

 spring ; but if the females often prefer strangers to their old 

 companions, as seems to be the case, according to Nordenskiold, in 

 Siberia, and in Syria as shown in the following essay, then we can 

 readily understand how rapid and complete would be the progress of 

 mongrelization. I will now give without further comment the essay 

 which Dr. W. Van Dyck, Lecturer on Zoology to the Protestant 

 College at Beyrout, who has had excellent opportunities for obser- 

 vations during a residence of twenty years, has been so kind as to 

 send me. 



On the Modification of a Race of Syrian Slreet-Doffs hy means 

 of Sexual Selection. By W. Van Dyck, AI.D. 



Beyrout is one of the principal ports on the Syrian coast, and has 

 a population of from eighty to one hundred thousand. Like most 

 Oriental cities, its system of street-cleansing is far from perfect, and 

 much of the scavenging is left to the street-dogs, many hundreds of 

 which roam at large through the town and suburbs, picking up a sub- 

 sistence as they best can. Twenty years ago, and previously, these 

 dogs were quite a homogeneous race, the following being a rough 

 description of a typical specimen : — height at shoulder, 20-22 in. ; 

 length from muzzle to root of tail 32-34 in. ; length of tail, 12-15 in. ; 

 colour sandy grey, with some variety of shades (rarely so light as to 

 pass for dirty white), in most cases distinctly darker above than 

 beneath, and not unfrequently grizzled or brindled ; head of medium 

 size, with rather pointed snout and small pointed semipendulous ears ; 

 tail bushy, usually carried up over the back, sometimes much curled ; 

 general aspect decidedly jackal-like, or semi-wolfish ; disposition 

 cowardly, seldom savage. The only departures worthy of mention 

 from the above type, at the time of which I write, were occasional 

 black dogs, mostly with shorter hair than that of the sandy ones, 

 rarely piebald black-and-white specimens. At the present date, the 

 case is very different. The sandy-grey colour still prevails, it is true ; 

 but there is hardly an imaginable colour or combination of colours 



' • Naturgeschichte der Siiiigethiere vou Paraguay,' 1830, p. 154. 



25* 



