20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I43 



be seen that many of the birds less than 200 grams in weight are 

 decidedly above this line, only the Rallidae, Cuculidae, and Podici- 

 pedidae falling below. 



Since the pectoralis (pectoralis superficialis or p. major) is the most 

 important muscle in depressing the wing, it was also treated separately 

 (fig. 2). It will be seen that the divergences from a straight line are 



PECTORALIS 



gr oms 



600 



200 



100 

 60 

 60 



40 

 20 



10 



8 



6 

 4 



PELECANIDiE. 

 CICOHIIDAE — • ^* 



CATHARTIDAE 

 CRACIOAE ^PANDIONIDAE 



ARAMIOAE \ _- — NUMIDlOAE 

 THRESKIORNITHIDAE^ *^^-ANHlNGIDAE 



FALCONIDAE-^^ »- PH A LACROCORACI DAE 



ANATIDAE-* ^*^~- AC CI P I TRI DAE 



COCHLEARHDAE O^"'?/ 



PHASIANIDAE LARIDAE 



TINAMIDAE. ^ "^-TYTONIDAE 

 HOMOTtOAE 



»-RYNCHOPIDA£ 

 NYCTIBIIDAE 

 CHARADRIIOAE / ^ 



PSITTACIOAE I / -RAMPHASTIDAE 



STURNIOAE \ I / 



t^mP^AV . *~ C ft «-CEDI N I DA E 

 TROGONIDAE \ \\ . Bucr.nNinAF 



COLUMBIDAE \0* _-co H viOAE° 



1 Y _ RA " ,N ! 04 A\ ^~£— HELIORNITHIOAE 



BOMBYCILLIOAE \ 

 TURDIOAEv \ \ 

 PLOCEIOAE\l • 

 FURNARIIDAE \ \ 



FBINGII IIOAE \l V-JACANIDAE 



VODICIPEDIDAE 

 CUCULIDAE 

 CAPRIMULG1DAE 

 MIMI DAE 

 SCOLOPACIDAE 



E\ 



>AE \\ V _ 



PARULIDAE \V* *~~Z— FORMIC ARM DAE 



PIPRIOAE \»» ?•<<- J— -C APITONIBAE 



VIREONIDAE W\>0\. R A L L I D A£ 

 MOTACILLIDAE., \ \X N I C T E R 1 DA E 



HlRUNDINIDAE-^7 \\ P !A' °*.% 



oendrocolapt.dae' \ \ C0 S E ' R T E T ^ D A A E E 



TROCHILIDAE-* TROGLO0YT1DAE 

 •-•CERTHIIDAE 

 SYLVIIDAE. 

 1 Nl I 1 I | 1 1 I I I I L 



20 40 60 100 200 400600 1000 2000 4000 



BODY grams 



Fig. 2. — Selected plottings of pectoralis superficialis muscle weights against body weights 



(log scales). 



not only different, but sometimes greater than those observed for the 

 flight muscles as a whole. Those with a large pectoralis also have large 

 flight muscles, and vice versa. Examples of those with a relatively 

 large pectoralis are found in the tinamids, threskiornithids, anatids, 

 phasianids, charadriids, columbids, psittacids, trochilids, trogonids, 

 cotingids, motacillids, coerebids, and thraupids. Those with a rela- 

 tively small pectoralis are the podicipedids, phalacrocoracids, some 

 ardeids, some accipitrids, rallids, heliornithids, cuculids, formicariids, 

 and troglodytids. 



Although there is a tendency toward similarity among different 



