DR. GAMBEL ON THE BIRDS OF CALIFORNIA. 217 



This genus contains at least two well marked species differing in size and colour. 

 The G. affinis is much, smaller, with the bill quite moderate, and the plumage above 

 with reddish bronzed reflections ; beneath it is pale ochraceous, with the anal region 

 dusky rufous : the breast and sides of neck are sparsely marked with longitudinal 

 black streaks occupying the centres of the feathers. The G. mexicanus has the 

 upper plumage bronzed with steel blue and brownish green reflections. On the 

 breast and sides of neck the webs of the feathers are more loose and setaceous, black 

 in the centre, on either side, with broad reddish ochraceous margins ; all the rest of 

 the woolly feathers beneath of a dirty grey colour. 



Nothing is more remarkable in these birds than the variation in size to which the 

 bill is subject. This led me to suspect that among the specimens in the collection of 

 the Academy, there were four species, but finding scarcely any difference in the 

 other proportions or colour, I conclude that the bill is subject to very great 

 modification in size and form according to age ; which, in fact, is the case in most of 

 the American cuculidse. 



In two specimens of the G. affinis the measurements of the bill are as follows : 



\st specimen. 2d specimen. 



Length of from nostril to tip, ... 8-lOtlis of an inch, 1 inch and 1-lOth. 



" " lower mandible from the junction of rami to tip, 5-lOths " T^-lOths of an inch. 



" from angle of mouth, ... 1 inch and 6^-lOths. 2 inches. 



The smaller one appears to be in perfect plumage, and its colours more brilliant 

 than in the one with the largest bill. The tail, wings and tarsi are nearly equal in both. 



A specimen of G. mexicanus brought from Buena Vista by one of the army 

 officers, is smaller in every way than the other specimens, but is a young bird. The 

 wing is half an inch shorter, the tarsus shorter, and the bill from angle of mouth 

 five-tenths of an inch shorter, and from nostril to tip one inch and two-tenths, instead 

 of one and a half inches. 



From Saurothera it only differs in the character of the plumage: the margins of 

 the mandibles are ragged, not serrated, in both; indeed the lacerated appearance is 

 most probably only the result of wear and tear, either in the living bird or in dried 

 specimens. 



It at first seemed strange to me that Boie should have placed this bird in his 

 genus Diplopteris, but if the very short-billed specimen of the G. affinis is compared 

 with Diplopteris ncevius it will be difficult to find a generic distinction 



COLUMBA, Linn. 



113 C. FASCUTA, Say. Band-tailed Pidgeon. 



C monilis, Vigors' Zool. Beechy's Voyage, pi. 26. 



