lO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I46 



and that Clamator was of one type, along with such genera as Cuculus, 

 Chrysococcyx, Surniculus, Tapera, and others, while Endynamis 

 was of the other, along with Scythrops and Dromococcyx. It must 

 be admitted that it is not wholly clear how significant this myological 

 character may be, as each group contains genera that seem only 

 distantly interrelated. Thus, in the former aggregate, Tapera is very 

 different from the rest, and in the latter group all three genera are 

 widely separated. 



Berger's anatomical studies, together with earlier work by Beddard, 

 Forbes, Fiirbringer, and others, give us our best evidence of relation- 

 ships within the family. All the characters, osteological, myological, 

 and even ecdysial, have one thing in common — they are all of suf- 

 ficiently nonfunctional nature as to make them seem relatively re- 

 moved from the effects of selection. Hence they may be looked upon 

 as phylogenetically conservative, and, to that degree, they are reliable 

 indices of relationship. Breeding habits, parasitic or otherwise, are 

 more amenable to change. In fact, one of the safest deductions that 

 may be made from a study of brood parasitism is that in all the 

 groups in which it occurs it is a secondary situation that arose in 

 stocks that were originally self -breeding. 



Inasmuch as all the members of the Cuculinae are parasitic, it 

 would seem that brood parasitism had already become established in 

 their common, remote, ancestral stock before they became dif- 

 ferentiated into the genera as we know them today. This differentia- 

 tion has resulted in a wide variety of end products, some 16 genera 

 with 46 species according to Peters' list (1940), which suggests a 

 long period for its operation. This, in turn, indicates a great antiquity 

 of brood parasitism in the group, an antiquity that the history of 

 Clamator suggests must date from pre-Pliocene or not later than 

 Pliocene time. 



In studying the genus Clamator we are fortunate in that consid- 

 erable information is available on the life histories of each of its four 

 species. The entire group has been considered by Baker and by 

 Jourdain, two of the principal students of cuckoos' eggs, as one in 

 which adaptive evolution in egg similarity to those of its usual hosts 

 has progressed as far and as successfully as in any genus of cuckoos. 

 Clamator is, therefore, a primitive group of highly evolved species, 

 a biological situation that is not infrequent despite its seemingly 

 paradoxical nature. As Baker (1942, p. 3) put it, ". . . perfection 

 or completeness in adaptation or evolution must depend upon time 

 . . . and therefore the most perfectly evolved egg need not and does 



